[PATCH bpf v2] xsk: Fix out of order segment free in __xsk_generic_xmit()

[PATCH bpf v2] xsk: Fix out of order segment free in __xsk_generic_xmit()

[e.kubanski]

Move xsk completion queue descriptor write-back to destructor.

Fix xsk descriptor management in completion queue. Descriptor
management mechanism didn't take care of situations where
completion queue submission can happen out-of-order to
descriptor write-back.

__xsk_generic_xmit() was assigning descriptor to slot right
after completion queue slot reservation. If multiple CPUs
access the same completion queue after xmit, this can result
in out-of-order submission of invalid descriptor batch.
SKB destructor call can submit descriptor batch that is
currently in use by other CPU, instead of correct transmitted
ones. This could result in User-Space <-> Kernel-Space data race.

Forbid possible out-of-order submissions:
CPU A: Reservation + Descriptor Write
CPU B: Reservation + Descriptor Write
CPU B: Submit (submitted first batch reserved by CPU A)
CPU A: Submit (submitted second batch reserved by CPU B)

Move Descriptor Write to submission phase:
CPU A: Reservation (only moves local writer)
CPU B: Reservation (only moves local writer)
CPU B: Descriptor Write + Submit
CPU A: Descriptor Write + Submit

This solves potential out-of-order free of xsk buffers.

Signed-off-by: Eryk Kubanski <e.kubanski@partner.samsung.com>
Fixes: e6c4047f5122 ("xsk: Use xsk_buff_pool directly for cq functions")
---
 include/linux/skbuff.h |  2 ++
 net/xdp/xsk.c          | 17 +++++++++++------
 net/xdp/xsk_queue.h    | 11 +++++++++++
 3 files changed, 24 insertions(+), 6 deletions(-)

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 5520524c93bf..cc37b62638cd 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -624,6 +624,8 @@ struct skb_shared_info {
 		void		*destructor_arg;
 	};
 
+	u64 xsk_descs[MAX_SKB_FRAGS];
+
 	/* must be last field, see pskb_expand_head() */
 	skb_frag_t	frags[MAX_SKB_FRAGS];
 };
diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c
index 72c000c0ae5f..2987e81482d7 100644
--- a/net/xdp/xsk.c
+++ b/net/xdp/xsk.c
@@ -528,24 +528,24 @@ static int xsk_wakeup(struct xdp_sock *xs, u8 flags)
 	return dev->netdev_ops->ndo_xsk_wakeup(dev, xs->queue_id, flags);
 }
 
-static int xsk_cq_reserve_addr_locked(struct xsk_buff_pool *pool, u64 addr)
+static int xsk_cq_reserve_locked(struct xsk_buff_pool *pool)
 {
 	unsigned long flags;
 	int ret;
 
 	spin_lock_irqsave(&pool->cq_lock, flags);
-	ret = xskq_prod_reserve_addr(pool->cq, addr);
+	ret = xskq_prod_reserve(pool->cq);
 	spin_unlock_irqrestore(&pool->cq_lock, flags);
 
 	return ret;
 }
 
-static void xsk_cq_submit_locked(struct xsk_buff_pool *pool, u32 n)
+static void xsk_cq_submit_locked(struct xsk_buff_pool *pool, u64 *descs, u32 n)
 {
 	unsigned long flags;
 
 	spin_lock_irqsave(&pool->cq_lock, flags);
-	xskq_prod_submit_n(pool->cq, n);
+	xskq_prod_write_submit_addr_n(pool->cq, descs, n);
 	spin_unlock_irqrestore(&pool->cq_lock, flags);
 }
 
@@ -572,7 +572,9 @@ static void xsk_destruct_skb(struct sk_buff *skb)
 		*compl->tx_timestamp = ktime_get_tai_fast_ns();
 	}
 
-	xsk_cq_submit_locked(xdp_sk(skb->sk)->pool, xsk_get_num_desc(skb));
+	xsk_cq_submit_locked(xdp_sk(skb->sk)->pool,
+			     skb_shinfo(skb)->xsk_descs,
+			     xsk_get_num_desc(skb));
 	sock_wfree(skb);
 }
 
@@ -754,7 +756,9 @@ static struct sk_buff *xsk_build_skb(struct xdp_sock *xs,
 	skb->priority = READ_ONCE(xs->sk.sk_priority);
 	skb->mark = READ_ONCE(xs->sk.sk_mark);
 	skb->destructor = xsk_destruct_skb;
+
 	xsk_tx_metadata_to_compl(meta, &skb_shinfo(skb)->xsk_meta);
+	skb_shinfo(skb)->xsk_descs[xsk_get_num_desc(skb)] = desc->addr;
 	xsk_set_destructor_arg(skb);
 
 	return skb;
@@ -765,6 +769,7 @@ static struct sk_buff *xsk_build_skb(struct xdp_sock *xs,
 
 	if (err == -EOVERFLOW) {
 		/* Drop the packet */
+		skb_shinfo(xs->skb)->xsk_descs[xsk_get_num_desc(xs->skb)] = desc->addr;
 		xsk_set_destructor_arg(xs->skb);
 		xsk_drop_skb(xs->skb);
 		xskq_cons_release(xs->tx);
@@ -807,7 +812,7 @@ static int __xsk_generic_xmit(struct sock *sk)
 		 * if there is space in it. This avoids having to implement
 		 * any buffering in the Tx path.
 		 */
-		err = xsk_cq_reserve_addr_locked(xs->pool, desc.addr);
+		err = xsk_cq_reserve_locked(xs->pool);
 		if (err) {
 			err = -EAGAIN;
 			goto out;
diff --git a/net/xdp/xsk_queue.h b/net/xdp/xsk_queue.h
index 46d87e961ad6..06ce89aae217 100644
--- a/net/xdp/xsk_queue.h
+++ b/net/xdp/xsk_queue.h
@@ -436,6 +436,17 @@ static inline void xskq_prod_submit_n(struct xsk_queue *q, u32 nb_entries)
 	__xskq_prod_submit(q, q->ring->producer + nb_entries);
 }
 
+static inline void xskq_prod_write_submit_addr_n(struct xsk_queue *q, u64 *addrs, u32 nb_entries)
+{
+	struct xdp_umem_ring *ring = (struct xdp_umem_ring *)q->ring;
+	u32 prod = q->ring->producer;
+
+	for (u32 i = 0; i < nb_entries; ++i)
+		ring->desc[prod++ & q->ring_mask] = addrs[i];
+
+	__xskq_prod_submit(q, prod);
+}
+
 static inline bool xskq_prod_is_empty(struct xsk_queue *q)
 {
 	/* No barriers needed since data is not accessed */
-- 
2.34.1

RE: [PATCH bpf v2] xsk: Fix out of order segment free in __xsk_generic_xmit()

[Eryk Kubanski]

It seems that CI tests have failed:

First test_progs failure (test_progs-aarch64-gcc-14):
#610/3 xdp_adjust_tail/xdp_adjust_tail_grow2
...
test_xdp_adjust_tail_grow2:FAIL:case-128 retval unexpected case-128 retval: actual 1 != expected 3
test_xdp_adjust_tail_grow2:FAIL:case-128 data_size_out unexpected case-128 data_size_out: actual 128 != expected 3520
test_xdp_adjust_tail_grow2:FAIL:case-128-data cnt unexpected case-128-data cnt: actual 0 != expected 3392
test_xdp_adjust_tail_grow2:FAIL:case-128-data data_size_out unexpected case-128-data data_size_out: actual 128 != expected 3520
...
#620 xdp_do_redirect
...
test_max_pkt_size:FAIL:prog_run_max_size unexpected error: -22 (errno 22)

But Im not sure why?

My changes impact only AF_XDP generic_xmit functions, these bpf tests don't touch
AF_XDP sockets xmit path. Changes should impact only sendmsg socket syscall.
Most of changes are Translation Unit local to xsk module.
The only thing i think could impact that is skb_shared_info, but why?

xsk tests didn't fail. Could you help me figure it out?
Should I be worried? Maybe tests are broken?

Re: [PATCH bpf v2] xsk: Fix out of order segment free in __xsk_generic_xmit()

[Stanislav Fomichev]

On 05/30, e.kubanski wrote:
> Move xsk completion queue descriptor write-back to destructor.
> 
> Fix xsk descriptor management in completion queue. Descriptor
> management mechanism didn't take care of situations where
> completion queue submission can happen out-of-order to
> descriptor write-back.
> 
> __xsk_generic_xmit() was assigning descriptor to slot right
> after completion queue slot reservation. If multiple CPUs
> access the same completion queue after xmit, this can result
> in out-of-order submission of invalid descriptor batch.
> SKB destructor call can submit descriptor batch that is
> currently in use by other CPU, instead of correct transmitted
> ones. This could result in User-Space <-> Kernel-Space data race.
> 
> Forbid possible out-of-order submissions:
> CPU A: Reservation + Descriptor Write
> CPU B: Reservation + Descriptor Write
> CPU B: Submit (submitted first batch reserved by CPU A)
> CPU A: Submit (submitted second batch reserved by CPU B)
> 
> Move Descriptor Write to submission phase:
> CPU A: Reservation (only moves local writer)
> CPU B: Reservation (only moves local writer)
> CPU B: Descriptor Write + Submit
> CPU A: Descriptor Write + Submit
> 
> This solves potential out-of-order free of xsk buffers.

I'm not sure I understand what's the issue here. If you're using the
same XSK from different CPUs, you should take care of the ordering
yourself on the userspace side?

> Signed-off-by: Eryk Kubanski <e.kubanski@partner.samsung.com>
> Fixes: e6c4047f5122 ("xsk: Use xsk_buff_pool directly for cq functions")
> ---
>  include/linux/skbuff.h |  2 ++
>  net/xdp/xsk.c          | 17 +++++++++++------
>  net/xdp/xsk_queue.h    | 11 +++++++++++
>  3 files changed, 24 insertions(+), 6 deletions(-)
> 
> diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
> index 5520524c93bf..cc37b62638cd 100644
> --- a/include/linux/skbuff.h
> +++ b/include/linux/skbuff.h
> @@ -624,6 +624,8 @@ struct skb_shared_info {
>  		void		*destructor_arg;
>  	};
>  
> +	u64 xsk_descs[MAX_SKB_FRAGS];

This is definitely a no-go (sk_buff and skb_shared_info space is
precious).

RE: Re: [PATCH bpf v2] xsk: Fix out of order segment free in __xsk_generic_xmit()

[Eryk Kubanski]

> I'm not sure I understand what's the issue here. If you're using the
> same XSK from different CPUs, you should take care of the ordering
> yourself on the userspace side?

It's not a problem with user-space Completion Queue READER side.
Im talking exclusively about kernel-space Completion Queue WRITE side.

This problem can occur when multiple sockets are bound to the same
umem, device, queue id. In this situation Completion Queue is shared.
This means it can be accessed by multiple threads on kernel-side.
Any use is indeed protected by spinlock, however any write sequence
(Acquire write slot as writer, write to slot, submit write slot to reader)
isn't atomic in any way and it's possible to submit not-yet-sent packet
descriptors back to user-space as TX completed.

Up untill now, all write-back operations had two phases, each phase
locks the spinlock and unlocks it:
1) Acquire slot + Write descriptor (increase cached-writer by N + write values)
2) Submit slot to the reader (increase writer by N)

Slot submission was solely based on the timing. Let's consider situation,
where two different threads issue a syscall for two different AF_XDP sockets
that are bound to the same umem, dev, queue-id.

AF_XDP setup:
                                                            
                             kernel-space                   
                                                            
           Write   Read                                     
            +--+   +--+                                     
            |  |   |  |                                     
            |  |   |  |                                     
            |  |   |  |                                     
 Completion |  |   |  | Fill                                
 Queue      |  |   |  | Queue                               
            |  |   |  |                                     
            |  |   |  |                                     
            |  |   |  |                                     
            |  |   |  |                                     
            +--+   +--+                                     
            Read   Write                                    
                             user-space                     
                                                            
                                                            
   +--------+         +--------+                            
   | AF_XDP |         | AF_XDP |                            
   +--------+         +--------+                            
                                                            
                                                            
                                                            
                                                            

Possible out-of-order scenario:
                                                                                                                                       
                                                                                                                                       
                              writer         cached_writer1                      cached_writer2                                        
                                 |                 |                                   |                                               
                                 |                 |                                   |                                               
                                 |                 |                                   |                                               
                                 |                 |                                   |                                               
                  +--------------|--------|--------|--------|--------|--------|--------|----------------------------------------------+
                  |              |        |        |        |        |        |        |                                              |
 Completion Queue |              |        |        |        |        |        |        |                                              |
                  |              |        |        |        |        |        |        |                                              |
                  +--------------|--------|--------|--------|--------|--------|--------|----------------------------------------------+
                                 |                 |                                   |                                               
                                 |                 |                                   |                                               
                                 |-----------------|                                   |                                               
                                  A) T1 syscall    |                                   |                                               
                                  writes 2         |                                   |                                               
                                  descriptors      |-----------------------------------|                                               
                                                    B) T2 syscall writes 4 descriptors                                                 
                                                                                                                                       
                                                                                                                                       
                                                                                                                                       
                                                                                                                                       
                 Notes:                                                                                                                
                 1) T1 and T2 AF_XDP sockets are two different sockets,                                                                
                    __xsk_generic_xmit will obtain two different mutexes.                                                              
                 2) T1 and T2 can be executed simultaneously, there is no                                                              
                    critical section whatsoever between them.                                                                          
                 3) T1 and T2 will obtain Completion Queue Lock for acquire + write,                                                   
                    only slot acquire + write are under lock.                                                                          
                 4) T1 and T2 completion (skb destructor)                                                                              
                    doesn't need to be the same order as A) and B).                                                                    
                 5) What if T1 fails after T2 acquires slots?                                                                          
                    cached_writer will be decreased by 2, T2 will                                                                      
                    submit failed descriptors of T1 (they shall be
                    retransmitted in next TX).                                                                                   
                    Submission of writer will move writer by 4 slots                                                                   
                    2 of these slots have failed T1 values. Last two
                    slots of T2 will be missing, descriptor leak.                                                                            
                 6) What if T2 completes before T1? writer will be                                                                     
                    moved by 4 slots. 2 of them are slots filled by T1.                                                                
                    T2 will complete 2 own slots and 2 slots of T1, It's bad.                                                          
                    T1 will complete last 2 slots of T2, also bad.                                                                     

This out-of-order completion can effectively cause User-space <-> Kernel-space
data race. This patch solves that, by only acquiring cached_writer first and
do the completion (sumission (write + increase writer)) after. This is the only
way to make that bulletproof for multithreaded access, failures and
out-of-order skb completions.

> This is definitely a no-go (sk_buff and skb_shared_info space is
> precious).

Okay so where should I store It? Can you give me some advice?

I left that there, because there is every information related to
skb desctruction. Additionally this is the only place in skb related
code that defines anything related to xsk: metadata, number of descriptors.
SKBUFF doesn't. I need to hold this information somewhere, and skbuff or
skb_shared_info are the only place I can store it. This need to be invariant
across all skb fragments, and be released after skb completes.

Re: Re: [PATCH bpf v2] xsk: Fix out of order segment free in __xsk_generic_xmit()

[Stanislav Fomichev]

On 06/02, Eryk Kubanski wrote:
> > I'm not sure I understand what's the issue here. If you're using the
> > same XSK from different CPUs, you should take care of the ordering
> > yourself on the userspace side?
> 
> It's not a problem with user-space Completion Queue READER side.
> Im talking exclusively about kernel-space Completion Queue WRITE side.
> 
> This problem can occur when multiple sockets are bound to the same
> umem, device, queue id. In this situation Completion Queue is shared.
> This means it can be accessed by multiple threads on kernel-side.
> Any use is indeed protected by spinlock, however any write sequence
> (Acquire write slot as writer, write to slot, submit write slot to reader)
> isn't atomic in any way and it's possible to submit not-yet-sent packet
> descriptors back to user-space as TX completed.
> 
> Up untill now, all write-back operations had two phases, each phase
> locks the spinlock and unlocks it:
> 1) Acquire slot + Write descriptor (increase cached-writer by N + write values)
> 2) Submit slot to the reader (increase writer by N)
> 
> Slot submission was solely based on the timing. Let's consider situation,
> where two different threads issue a syscall for two different AF_XDP sockets
> that are bound to the same umem, dev, queue-id.
> 
> AF_XDP setup:
>                                                             
>                              kernel-space                   
>                                                             
>            Write   Read                                     
>             +--+   +--+                                     
>             |  |   |  |                                     
>             |  |   |  |                                     
>             |  |   |  |                                     
>  Completion |  |   |  | Fill                                
>  Queue      |  |   |  | Queue                               
>             |  |   |  |                                     
>             |  |   |  |                                     
>             |  |   |  |                                     
>             |  |   |  |                                     
>             +--+   +--+                                     
>             Read   Write                                    
>                              user-space                     
>                                                             
>                                                             
>    +--------+         +--------+                            
>    | AF_XDP |         | AF_XDP |                            
>    +--------+         +--------+                            
>                                                             
>                                                             
>                                                             
>                                                             
> 
> Possible out-of-order scenario:
>                                                                                                                                        
>                                                                                                                                        
>                               writer         cached_writer1                      cached_writer2                                        
>                                  |                 |                                   |                                               
>                                  |                 |                                   |                                               
>                                  |                 |                                   |                                               
>                                  |                 |                                   |                                               
>                   +--------------|--------|--------|--------|--------|--------|--------|----------------------------------------------+
>                   |              |        |        |        |        |        |        |                                              |
>  Completion Queue |              |        |        |        |        |        |        |                                              |
>                   |              |        |        |        |        |        |        |                                              |
>                   +--------------|--------|--------|--------|--------|--------|--------|----------------------------------------------+
>                                  |                 |                                   |                                               
>                                  |                 |                                   |                                               
>                                  |-----------------|                                   |                                               
>                                   A) T1 syscall    |                                   |                                               
>                                   writes 2         |                                   |                                               
>                                   descriptors      |-----------------------------------|                                               
>                                                     B) T2 syscall writes 4 descriptors                                                 
>                                                                                                                                        
>                                                                                                                                        
>                                                                                                                                        
>                                                                                                                                        
>                  Notes:                                                                                                                
>                  1) T1 and T2 AF_XDP sockets are two different sockets,                                                                
>                     __xsk_generic_xmit will obtain two different mutexes.                                                              
>                  2) T1 and T2 can be executed simultaneously, there is no                                                              
>                     critical section whatsoever between them.                                                                          

XSK represents a single queue and each queue is single producer single
consumer. The fact that you can dup a socket and call sendmsg from
different threads/processes does not lift that restriction. I think
if you add synchronization on the userspace (lock(); sendmsg();
unlock();), that should help, right?

RE: Re: Re: [PATCH bpf v2] xsk: Fix out of order segment free in __xsk_generic_xmit()

[Eryk Kubanski]

> XSK represents a single queue and each queue is single producer single
> consumer. The fact that you can dup a socket and call sendmsg from
> different threads/processes does not lift that restriction. I think
> if you add synchronization on the userspace (lock(); sendmsg();
> unlock();), that should help, right?

It's not dup() of fd, It's perfectly legal AF_XDP setup.

You can share single device queue between multiple AF_XDP sockets.
Then RX and TX queue are per socket, while FILL / COMP are per
queue id of device. Access to FILL and COMP must be synchronized
on both user-space and kernel-space side.

https://docs.kernel.org/networking/af_xdp.html

> XDP_SHARED_UMEM bind flag
> This flag enables you to bind multiple sockets to the same UMEM.
> It works on the same queue id, between queue ids and between netdevs/devices.
> In this mode, each socket has their own RX and TX rings as usual, but you are going
> to have one or more FILL and COMPLETION ring pairs. You have to create one of these
> pairs per unique netdev and queue id tuple that you bind to.

Im not using sendmsg on dupped socket descriptor. It's just
another socket bound to the same netdev, queue id pair.

Even if that was the case, calling sendmsg on multiple
threads should be perfectly legal in this situation.
But i don't do that, each socket is handled exclusively
by single thread.

This is simply one of available AF_XDP deployments.
It should just work.
I don't need to introduce any locking scheme on my own
except FILL/COMP queue locking, which I did.

Definetly holding single netdevice-wide lock for any
RX/TX operation isn't an option. It should just work.

This problem is definetly in kernel. Provided explanation
clearly proves It. It's caught red handed. Please analyze
the code and see it for yourself.

Re: Re: [PATCH bpf v2] xsk: Fix out of order segment free in __xsk_generic_xmit()

[Maciej Fijalkowski]

On Mon, Jun 02, 2025 at 08:28:51AM -0700, Stanislav Fomichev wrote:
> On 06/02, Eryk Kubanski wrote:
> > > I'm not sure I understand what's the issue here. If you're using the
> > > same XSK from different CPUs, you should take care of the ordering
> > > yourself on the userspace side?
> > 
> > It's not a problem with user-space Completion Queue READER side.
> > Im talking exclusively about kernel-space Completion Queue WRITE side.
> > 
> > This problem can occur when multiple sockets are bound to the same
> > umem, device, queue id. In this situation Completion Queue is shared.
> > This means it can be accessed by multiple threads on kernel-side.
> > Any use is indeed protected by spinlock, however any write sequence
> > (Acquire write slot as writer, write to slot, submit write slot to reader)
> > isn't atomic in any way and it's possible to submit not-yet-sent packet
> > descriptors back to user-space as TX completed.
> > 
> > Up untill now, all write-back operations had two phases, each phase
> > locks the spinlock and unlocks it:
> > 1) Acquire slot + Write descriptor (increase cached-writer by N + write values)
> > 2) Submit slot to the reader (increase writer by N)
> > 
> > Slot submission was solely based on the timing. Let's consider situation,
> > where two different threads issue a syscall for two different AF_XDP sockets
> > that are bound to the same umem, dev, queue-id.
> > 
> > AF_XDP setup:
> >                                                             
> >                              kernel-space                   
> >                                                             
> >            Write   Read                                     
> >             +--+   +--+                                     
> >             |  |   |  |                                     
> >             |  |   |  |                                     
> >             |  |   |  |                                     
> >  Completion |  |   |  | Fill                                
> >  Queue      |  |   |  | Queue                               
> >             |  |   |  |                                     
> >             |  |   |  |                                     
> >             |  |   |  |                                     
> >             |  |   |  |                                     
> >             +--+   +--+                                     
> >             Read   Write                                    
> >                              user-space                     
> >                                                             
> >                                                             
> >    +--------+         +--------+                            
> >    | AF_XDP |         | AF_XDP |                            
> >    +--------+         +--------+                            
> >                                                             
> >                                                             
> >                                                             
> >                                                             
> > 
> > Possible out-of-order scenario:
> >                                                                                                                                        
> >                                                                                                                                        
> >                               writer         cached_writer1                      cached_writer2                                        
> >                                  |                 |                                   |                                               
> >                                  |                 |                                   |                                               
> >                                  |                 |                                   |                                               
> >                                  |                 |                                   |                                               
> >                   +--------------|--------|--------|--------|--------|--------|--------|----------------------------------------------+
> >                   |              |        |        |        |        |        |        |                                              |
> >  Completion Queue |              |        |        |        |        |        |        |                                              |
> >                   |              |        |        |        |        |        |        |                                              |
> >                   +--------------|--------|--------|--------|--------|--------|--------|----------------------------------------------+
> >                                  |                 |                                   |                                               
> >                                  |                 |                                   |                                               
> >                                  |-----------------|                                   |                                               
> >                                   A) T1 syscall    |                                   |                                               
> >                                   writes 2         |                                   |                                               
> >                                   descriptors      |-----------------------------------|                                               
> >                                                     B) T2 syscall writes 4 descriptors                                                 
> >                                                                                                                                        
> >                                                                                                                                        
> >                                                                                                                                        
> >                                                                                                                                        
> >                  Notes:                                                                                                                
> >                  1) T1 and T2 AF_XDP sockets are two different sockets,                                                                
> >                     __xsk_generic_xmit will obtain two different mutexes.                                                              
> >                  2) T1 and T2 can be executed simultaneously, there is no                                                              
> >                     critical section whatsoever between them.                                                                          
> 
> XSK represents a single queue and each queue is single producer single
> consumer. The fact that you can dup a socket and call sendmsg from
> different threads/processes does not lift that restriction. I think
> if you add synchronization on the userspace (lock(); sendmsg();
> unlock();), that should help, right?

Eryk, can you tell us a bit more about HW you're using? The problem you
described simply can not happen for HW with in-order completions. You
can't complete descriptor from slot 5 without going through completion of
slot 3. So our assumption is you're using HW with out-of-order
completions, correct?

If that is the case then we have to think about possible solutions which
probably won't be straight-forward. As Stan said current fix is a no-go.

RE: Re: Re: [PATCH bpf v2] xsk: Fix out of order segment free in __xsk_generic_xmit()

[Eryk Kubanski]

> Eryk, can you tell us a bit more about HW you're using? The problem you
> described simply can not happen for HW with in-order completions. You
> can't complete descriptor from slot 5 without going through completion of
> slot 3. So our assumption is you're using HW with out-of-order
> completions, correct?

Maciej this isn't reproduced on any hardware.
I found this bug while working on generic AF_XDP.

We're using MACVLAN deployment where, two or more
sockets share single MACVLAN device queue.
It doesn't even need to go out of host...

SKB doesn't even need to complete in this case
to observe this bug. It's enough if earlier writer
just fails after descriptor write. This case is
writen in my diagram Notes 5).

Are you sure that __dev_direct_xmit will keep
the packets on the same thread? What's about
NAPI, XPS, IRQs, etc?

If sendmsg() is issued by two threads, you don't
know which one will complete faster. You can still
have out-of-order completion in relation to
descrpitor CQ write.

This isn't problem with out-of-order HW completion,
but the problem with out-of-order completion in relation
to sendmsg() call and descriptor write.

But this doesn't even need to be sent, as I
explained above, situation where one of threads
fails is more than enough to catch that bug.

> If that is the case then we have to think about possible solutions which
> probably won't be straight-forward. As Stan said current fix is a no-go.

Okay what is your idea? In my opinion the only
thing I can do is to just push the descriptors
before or after __dev_direct_xmit() and keep
these descriptors in some stack array.
However this won't be compatible with behaviour
of DRV deployed AF_XDP. Descriptors will be returned
right after copy to SKB instead of after SKB is sent.
If this is fine for you, It's fine for me.

Otherwise this need to be tied to SKB lifetime,
but how?

Re: Re: Re: [PATCH bpf v2] xsk: Fix out of order segment free in __xsk_generic_xmit()

[Maciej Fijalkowski]

On Mon, Jun 02, 2025 at 06:18:57PM +0200, Eryk Kubanski wrote:
> > Eryk, can you tell us a bit more about HW you're using? The problem you
> > described simply can not happen for HW with in-order completions. You
> > can't complete descriptor from slot 5 without going through completion of
> > slot 3. So our assumption is you're using HW with out-of-order
> > completions, correct?
> 
> Maciej this isn't reproduced on any hardware.
> I found this bug while working on generic AF_XDP.
> 
> We're using MACVLAN deployment where, two or more
> sockets share single MACVLAN device queue.
> It doesn't even need to go out of host...
> 
> SKB doesn't even need to complete in this case
> to observe this bug. It's enough if earlier writer
> just fails after descriptor write. This case is
> writen in my diagram Notes 5).

Thanks for shedding a bit more light on it. In the future it would be nice
if you would be able to come up with a reproducer of a bug that others
could use on their side. Plus the overview of your deployment from the
beginning would also help with people understanding the issue :)

> 
> Are you sure that __dev_direct_xmit will keep
> the packets on the same thread? What's about
> NAPI, XPS, IRQs, etc?
> 
> If sendmsg() is issued by two threads, you don't
> know which one will complete faster. You can still
> have out-of-order completion in relation to
> descrpitor CQ write.
> 
> This isn't problem with out-of-order HW completion,
> but the problem with out-of-order completion in relation
> to sendmsg() call and descriptor write.
> 
> But this doesn't even need to be sent, as I
> explained above, situation where one of threads
> fails is more than enough to catch that bug.
> 
> > If that is the case then we have to think about possible solutions which
> > probably won't be straight-forward. As Stan said current fix is a no-go.
> 
> Okay what is your idea? In my opinion the only
> thing I can do is to just push the descriptors
> before or after __dev_direct_xmit() and keep
> these descriptors in some stack array.
> However this won't be compatible with behaviour
> of DRV deployed AF_XDP. Descriptors will be returned
> right after copy to SKB instead of after SKB is sent.
> If this is fine for you, It's fine for me.
> 
> Otherwise this need to be tied to SKB lifetime,
> but how?

I'm looking into it, bottom line is that we discussed it with Magnus and
agree that issue you're reporting needs to be addressed.

I'll get back to you to discuss potential way of attacking it.

Thanks!

RE: Re: Re: Re: [PATCH bpf v2] xsk: Fix out of order segment free in __xsk_generic_xmit()

[Eryk Kubanski]

> Thanks for shedding a bit more light on it. In the future it would be nice
> if you would be able to come up with a reproducer of a bug that others
> could use on their side. Plus the overview of your deployment from the
> beginning would also help with people understanding the issue :)

Sure, sorry for not giving that in advance, I found this issue
during code analysis, not during deployment.
It's not that simple to catch.
I thought that in finite time we will agree :D.
Next patchsets from me will have more information up-front.

> I'm looking into it, bottom line is that we discussed it with Magnus and
> agree that issue you're reporting needs to be addressed.
> I'll get back to you to discuss potential way of attacking it.
> Thanks!

Thank you.
Will this be discussed in the same mailing chain?

Technically we need to tie descriptor write-back
with skb lifetime.
xsk_build_skb() function builds skb for TX,
if i understand correctly this can work both ways
either we perform zero-copy, so specific buffer
page is attached to skb with given offset and size.
OR perform the copy.

If there was no zerocopy case, we could store it
on stack array and simply recycle descriptor back
right away without waiting for SKB completion.

This zero-copy case makes it impossible right?
We need to store these descriptors somewhere else
and tie it to SKB destruction :(.

Re: Re: Re: Re: [PATCH bpf v2] xsk: Fix out of order segment free in __xsk_generic_xmit()

[Maciej Fijalkowski]

On Wed, Jun 04, 2025 at 04:15:21PM +0200, Eryk Kubanski wrote:
> > Thanks for shedding a bit more light on it. In the future it would be nice
> > if you would be able to come up with a reproducer of a bug that others
> > could use on their side. Plus the overview of your deployment from the
> > beginning would also help with people understanding the issue :)
> 
> Sure, sorry for not giving that in advance, I found this issue
> during code analysis, not during deployment.
> It's not that simple to catch.
> I thought that in finite time we will agree :D.
> Next patchsets from me will have more information up-front.
> 
> > I'm looking into it, bottom line is that we discussed it with Magnus and
> > agree that issue you're reporting needs to be addressed.
> > I'll get back to you to discuss potential way of attacking it.
> > Thanks!
> 
> Thank you.
> Will this be discussed in the same mailing chain?

I've come with something as below. Idea is to embed addr at the end of
linear part of skb/at the end of page frag. For first case we account 8
more bytes when calling sock_alloc_send_skb(), for the latter we alloc
whole page anyways so we can just use the last 8 bytes. then in destructor
we have access to addrs used during xmit descriptor production. This
solution is free of additional struct members so performance-wise it
should not be as impactful as previous approach.

---
 net/xdp/xsk.c       | 37 ++++++++++++++++++++++++++++++-------
 net/xdp/xsk_queue.h |  8 ++++++++
 2 files changed, 38 insertions(+), 7 deletions(-)

diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c
index 72c000c0ae5f..22f314ea9dc2 100644
--- a/net/xdp/xsk.c
+++ b/net/xdp/xsk.c
@@ -528,24 +528,39 @@ static int xsk_wakeup(struct xdp_sock *xs, u8 flags)
 	return dev->netdev_ops->ndo_xsk_wakeup(dev, xs->queue_id, flags);
 }
 
-static int xsk_cq_reserve_addr_locked(struct xsk_buff_pool *pool, u64 addr)
+static int xsk_cq_reserve_locked(struct xsk_buff_pool *pool)
 {
 	unsigned long flags;
 	int ret;
 
 	spin_lock_irqsave(&pool->cq_lock, flags);
-	ret = xskq_prod_reserve_addr(pool->cq, addr);
+	ret = xskq_prod_reserve(pool->cq);
 	spin_unlock_irqrestore(&pool->cq_lock, flags);
 
 	return ret;
 }
 
-static void xsk_cq_submit_locked(struct xsk_buff_pool *pool, u32 n)
+static void xsk_cq_submit_locked(struct xsk_buff_pool *pool, struct sk_buff *skb)
 {
+	size_t addr_sz = sizeof(((struct xdp_desc *)0)->addr);
 	unsigned long flags;
+	int nr_frags, i;
+	u64 addr;
 
 	spin_lock_irqsave(&pool->cq_lock, flags);
-	xskq_prod_submit_n(pool->cq, n);
+
+	addr = *(u64 *)(skb->head + skb->end - addr_sz);
+	xskq_prod_write_addr(pool->cq, addr);
+
+	nr_frags = skb_shinfo(skb)->nr_frags;
+
+	for (i = 0; i < nr_frags; i++) {
+		skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
+
+		addr = *(u64 *)(skb_frag_address(frag) + PAGE_SIZE - addr_sz);
+		xskq_prod_write_addr(pool->cq, addr);
+	}
+
 	spin_unlock_irqrestore(&pool->cq_lock, flags);
 }
 
@@ -572,7 +587,7 @@ static void xsk_destruct_skb(struct sk_buff *skb)
 		*compl->tx_timestamp = ktime_get_tai_fast_ns();
 	}
 
-	xsk_cq_submit_locked(xdp_sk(skb->sk)->pool, xsk_get_num_desc(skb));
+	xsk_cq_submit_locked(xdp_sk(skb->sk)->pool, skb);
 	sock_wfree(skb);
 }
 
@@ -656,6 +671,7 @@ static struct sk_buff *xsk_build_skb_zerocopy(struct xdp_sock *xs,
 static struct sk_buff *xsk_build_skb(struct xdp_sock *xs,
 				     struct xdp_desc *desc)
 {
+	size_t addr_sz = sizeof(desc->addr);
 	struct xsk_tx_metadata *meta = NULL;
 	struct net_device *dev = xs->dev;
 	struct sk_buff *skb = xs->skb;
@@ -671,6 +687,7 @@ static struct sk_buff *xsk_build_skb(struct xdp_sock *xs,
 	} else {
 		u32 hr, tr, len;
 		void *buffer;
+		u8 *trailer;
 
 		buffer = xsk_buff_raw_get_data(xs->pool, desc->addr);
 		len = desc->len;
@@ -680,7 +697,9 @@ static struct sk_buff *xsk_build_skb(struct xdp_sock *xs,
 
 			hr = max(NET_SKB_PAD, L1_CACHE_ALIGN(dev->needed_headroom));
 			tr = dev->needed_tailroom;
-			skb = sock_alloc_send_skb(&xs->sk, hr + len + tr, 1, &err);
+			skb = sock_alloc_send_skb(&xs->sk,
+						  hr + len + tr + addr_sz,
+						  1, &err);
 			if (unlikely(!skb))
 				goto free_err;
 
@@ -690,6 +709,9 @@ static struct sk_buff *xsk_build_skb(struct xdp_sock *xs,
 			err = skb_store_bits(skb, 0, buffer, len);
 			if (unlikely(err))
 				goto free_err;
+			trailer = skb->head + skb->end - addr_sz;
+			memcpy(trailer, &desc->addr, addr_sz);
+
 		} else {
 			int nr_frags = skb_shinfo(skb)->nr_frags;
 			struct page *page;
@@ -708,6 +730,7 @@ static struct sk_buff *xsk_build_skb(struct xdp_sock *xs,
 
 			vaddr = kmap_local_page(page);
 			memcpy(vaddr, buffer, len);
+			memcpy(vaddr + PAGE_SIZE - addr_sz, &desc->addr, addr_sz);
 			kunmap_local(vaddr);
 
 			skb_add_rx_frag(skb, nr_frags, page, 0, len, PAGE_SIZE);
@@ -807,7 +830,7 @@ static int __xsk_generic_xmit(struct sock *sk)
 		 * if there is space in it. This avoids having to implement
 		 * any buffering in the Tx path.
 		 */
-		err = xsk_cq_reserve_addr_locked(xs->pool, desc.addr);
+		err = xsk_cq_reserve_locked(xs->pool);
 		if (err) {
 			err = -EAGAIN;
 			goto out;
diff --git a/net/xdp/xsk_queue.h b/net/xdp/xsk_queue.h
index 46d87e961ad6..9cd65d1bc81b 100644
--- a/net/xdp/xsk_queue.h
+++ b/net/xdp/xsk_queue.h
@@ -390,6 +390,14 @@ static inline int xskq_prod_reserve_addr(struct xsk_queue *q, u64 addr)
 	return 0;
 }
 
+static inline void xskq_prod_write_addr(struct xsk_queue *q, u64 addr)
+{
+	struct xdp_umem_ring *ring = (struct xdp_umem_ring *)q->ring;
+
+	/* A, matches D */
+	ring->desc[q->ring->producer++ & q->ring_mask] = addr;
+}
+
 static inline void xskq_prod_write_addr_batch(struct xsk_queue *q, struct xdp_desc *descs,
 					      u32 nb_entries)
 {


> 
> Technically we need to tie descriptor write-back
> with skb lifetime.
> xsk_build_skb() function builds skb for TX,
> if i understand correctly this can work both ways
> either we perform zero-copy, so specific buffer
> page is attached to skb with given offset and size.
> OR perform the copy.
> 
> If there was no zerocopy case, we could store it
> on stack array and simply recycle descriptor back
> right away without waiting for SKB completion.
> 
> This zero-copy case makes it impossible right?
> We need to store these descriptors somewhere else
> and tie it to SKB destruction :(.

RE: Re: Re: Re: Re: [PATCH bpf v2] xsk: Fix out of order segment free in __xsk_generic_xmit()

[Eryk Kubanski]

xsk_build_skb() doesn't seem to handle
zerocopy case in that situation.
(IFF_TX_SKB_NO_LINEAR device flag)

How to return descriptors back after
building skb in zerocopy mode?
How does it work in this situation?

RE: Re: Re: Re: Re: [PATCH bpf v2] xsk: Fix out of order segment free in __xsk_generic_xmit()

[Eryk Kubanski]

> I've come with something as below. Idea is to embed addr at the end of
> linear part of skb/at the end of page frag.

Are you sure that this is safe for other components?

So instead of storing entire array at the skb_shared_info (skb->end),
we store It 8-bytes per PAGE fragment and 8-byte at skb->end.
Technically noone should edit skb past-the-end, it
looks good to me.

In xsk_cq_submit_locked() you use only xskq_prod_write_addr.
I think that this may cause synchronization issues on reader side.
You don't perform ATOMIC_RELEASE, so this producer incrementation
is atomic (u32) but it doesn't synchronize address write.

I think that you should accumulate local producer and
store it with ATOMIC_RELEASE after writing descriptors.
In current situation someone may see producer incrementation,
but address stored in this bank doesn't need to be synchronized yet.

Re: Re: Re: Re: Re: [PATCH bpf v2] xsk: Fix out of order segment free in __xsk_generic_xmit()

[Maciej Fijalkowski]

On Tue, Jun 10, 2025 at 11:11:25AM +0200, Eryk Kubanski wrote:
> > I've come with something as below. Idea is to embed addr at the end of
> > linear part of skb/at the end of page frag.
> 
> Are you sure that this is safe for other components?
> 
> So instead of storing entire array at the skb_shared_info (skb->end),
> we store It 8-bytes per PAGE fragment and 8-byte at skb->end.
> Technically noone should edit skb past-the-end, it
> looks good to me.
> 
> In xsk_cq_submit_locked() you use only xskq_prod_write_addr.
> I think that this may cause synchronization issues on reader side.
> You don't perform ATOMIC_RELEASE, so this producer incrementation
> is atomic (u32) but it doesn't synchronize address write.
> 
> I think that you should accumulate local producer and
> store it with ATOMIC_RELEASE after writing descriptors.
> In current situation someone may see producer incrementation,
> but address stored in this bank doesn't need to be synchronized yet.

Hi Eryk, yes I missed the smp_store_release that __xskq_prod_submit does -
magic of late night refactors :) but main point was to share the approach
in terms of addr storage.

As you also said IFF_TX_SKB_NO_LINEAR case needs to be addressed as well
as it uses the same skb destructor. Since these pages come directly from
umem we don't need this quirk, we should be able to get the addr from
page.

Re: Re: [PATCH bpf v2] xsk: Fix out of order segment free in __xsk_generic_xmit()

[Jason Xing]

On Mon, Jun 2, 2025 at 5:28 PM Eryk Kubanski
<e.kubanski@partner.samsung.com> wrote:
>
> > I'm not sure I understand what's the issue here. If you're using the
> > same XSK from different CPUs, you should take care of the ordering
> > yourself on the userspace side?
>
> It's not a problem with user-space Completion Queue READER side.
> Im talking exclusively about kernel-space Completion Queue WRITE side.
>
> This problem can occur when multiple sockets are bound to the same
> umem, device, queue id. In this situation Completion Queue is shared.
> This means it can be accessed by multiple threads on kernel-side.
> Any use is indeed protected by spinlock, however any write sequence
> (Acquire write slot as writer, write to slot, submit write slot to reader)
> isn't atomic in any way and it's possible to submit not-yet-sent packet
> descriptors back to user-space as TX completed.
>
> Up untill now, all write-back operations had two phases, each phase
> locks the spinlock and unlocks it:
> 1) Acquire slot + Write descriptor (increase cached-writer by N + write values)
> 2) Submit slot to the reader (increase writer by N)
>
> Slot submission was solely based on the timing. Let's consider situation,
> where two different threads issue a syscall for two different AF_XDP sockets
> that are bound to the same umem, dev, queue-id.
>
> AF_XDP setup:
>
>                              kernel-space
>
>            Write   Read
>             +--+   +--+
>             |  |   |  |
>             |  |   |  |
>             |  |   |  |
>  Completion |  |   |  | Fill
>  Queue      |  |   |  | Queue
>             |  |   |  |
>             |  |   |  |
>             |  |   |  |
>             |  |   |  |
>             +--+   +--+
>             Read   Write
>                              user-space
>
>
>    +--------+         +--------+
>    | AF_XDP |         | AF_XDP |
>    +--------+         +--------+
>
>
>
>
>
> Possible out-of-order scenario:
>
>
>                               writer         cached_writer1                      cached_writer2
>                                  |                 |                                   |
>                                  |                 |                                   |
>                                  |                 |                                   |
>                                  |                 |                                   |
>                   +--------------|--------|--------|--------|--------|--------|--------|----------------------------------------------+
>                   |              |        |        |        |        |        |        |                                              |
>  Completion Queue |              |        |        |        |        |        |        |                                              |
>                   |              |        |        |        |        |        |        |                                              |
>                   +--------------|--------|--------|--------|--------|--------|--------|----------------------------------------------+
>                                  |                 |                                   |
>                                  |                 |                                   |
>                                  |-----------------|                                   |
>                                   A) T1 syscall    |                                   |
>                                   writes 2         |                                   |
>                                   descriptors      |-----------------------------------|
>                                                     B) T2 syscall writes 4 descriptors
>

Hi ALL,

Since Maciej posted a related patch to fix this issue, it took me a
little while to trace back to this thread. So here we are.

>                  Notes:
>                  1) T1 and T2 AF_XDP sockets are two different sockets,
>                     __xsk_generic_xmit will obtain two different mutexes.
>                  2) T1 and T2 can be executed simultaneously, there is no
>                     critical section whatsoever between them.
>                  3) T1 and T2 will obtain Completion Queue Lock for acquire + write,
>                     only slot acquire + write are under lock.
>                  4) T1 and T2 completion (skb destructor)
>                     doesn't need to be the same order as A) and B).
>                  5) What if T1 fails after T2 acquires slots?

What does it mean by 'fails'. Could you point out the accurate
function you said?

>                     cached_writer will be decreased by 2, T2 will
>                     submit failed descriptors of T1 (they shall be
>                     retransmitted in next TX).
>                     Submission of writer will move writer by 4 slots
>                     2 of these slots have failed T1 values. Last two
>                     slots of T2 will be missing, descriptor leak.

I wonder why the leak problem happens? IIUC, in the
__xsk_generic_xmit() + copy mode, xsk only tries to send the
descriptor from its own tx ring to the driver, like virtio_net as an
example. As you said, there are two xsks running in parallel. Why
could T2 send the descriptors that T1 puts into the completion queue?
__dev_direct_xmit() only passes the @skb that is built based on the
addr from per xsk tx ring.

Here are some maps related to the process you talked about:
case 1)
// T1 writes 2 descs in cq
[--1--][--2--][-null-][-null-][-null-][-null-][-null-]
                      |
                      cached_prod

// T1 fails because of NETDEV_TX_BUSY, and cq.cached_prod is decreased by 2.
[-null-][-null-][-null-][-null-][-null-][-null-][-null-]
     |
     cached_prod

// T2 starts to write at the first unused descs
[--1--][--2--][--3--][--4--][-null-][-null-][-null-]
                                        |
                                        cached_prod
So why can T2 send out the descs belonging to T1? In
__xsk_generic_xmit(), xsk_cq_reserve_addr_locked() initialises the
addr of acquired desc so it overwrites the invalid one previously
owned by T1. The addr is from per xsk tx ring... I'm lost. Could you
please share the detailed/key functions to shed more lights on this?
Thanks in advance.

I know you're not running on the (virtual) nic actually, but I still
want to know the possibility of the issue with normal end-to-end
transmission. In the virtio_net driver, __dev_direct_xmit() returns
BUSY only if the BQL takes effect, so your case might not happen here?
The reason why I asked is that I have a similar use case with
virtio_net and I am trying to understand whether it can happen in the
future.

Thanks,
Jason


>                  6) What if T2 completes before T1? writer will be
>                     moved by 4 slots. 2 of them are slots filled by T1.
>                     T2 will complete 2 own slots and 2 slots of T1, It's bad.
>                     T1 will complete last 2 slots of T2, also bad.
>
> This out-of-order completion can effectively cause User-space <-> Kernel-space
> data race. This patch solves that, by only acquiring cached_writer first and
> do the completion (sumission (write + increase writer)) after. This is the only
> way to make that bulletproof for multithreaded access, failures and
> out-of-order skb completions.
>
> > This is definitely a no-go (sk_buff and skb_shared_info space is
> > precious).
>
> Okay so where should I store It? Can you give me some advice?
>
> I left that there, because there is every information related to
> skb desctruction. Additionally this is the only place in skb related
> code that defines anything related to xsk: metadata, number of descriptors.
> SKBUFF doesn't. I need to hold this information somewhere, and skbuff or
> skb_shared_info are the only place I can store it. This need to be invariant
> across all skb fragments, and be released after skb completes.
>

Re: Re: [PATCH bpf v2] xsk: Fix out of order segment free in __xsk_generic_xmit()

[Maciej Fijalkowski]

On Fri, Jul 04, 2025 at 07:37:22AM +0800, Jason Xing wrote:
> On Mon, Jun 2, 2025 at 5:28 PM Eryk Kubanski
> <e.kubanski@partner.samsung.com> wrote:
> >
> > > I'm not sure I understand what's the issue here. If you're using the
> > > same XSK from different CPUs, you should take care of the ordering
> > > yourself on the userspace side?
> >
> > It's not a problem with user-space Completion Queue READER side.
> > Im talking exclusively about kernel-space Completion Queue WRITE side.
> >
> > This problem can occur when multiple sockets are bound to the same
> > umem, device, queue id. In this situation Completion Queue is shared.
> > This means it can be accessed by multiple threads on kernel-side.
> > Any use is indeed protected by spinlock, however any write sequence
> > (Acquire write slot as writer, write to slot, submit write slot to reader)
> > isn't atomic in any way and it's possible to submit not-yet-sent packet
> > descriptors back to user-space as TX completed.
> >
> > Up untill now, all write-back operations had two phases, each phase
> > locks the spinlock and unlocks it:
> > 1) Acquire slot + Write descriptor (increase cached-writer by N + write values)
> > 2) Submit slot to the reader (increase writer by N)
> >
> > Slot submission was solely based on the timing. Let's consider situation,
> > where two different threads issue a syscall for two different AF_XDP sockets
> > that are bound to the same umem, dev, queue-id.
> >
> > AF_XDP setup:
> >
> >                              kernel-space
> >
> >            Write   Read
> >             +--+   +--+
> >             |  |   |  |
> >             |  |   |  |
> >             |  |   |  |
> >  Completion |  |   |  | Fill
> >  Queue      |  |   |  | Queue
> >             |  |   |  |
> >             |  |   |  |
> >             |  |   |  |
> >             |  |   |  |
> >             +--+   +--+
> >             Read   Write
> >                              user-space
> >
> >
> >    +--------+         +--------+
> >    | AF_XDP |         | AF_XDP |
> >    +--------+         +--------+
> >
> >
> >
> >
> >
> > Possible out-of-order scenario:
> >
> >
> >                               writer         cached_writer1                      cached_writer2
> >                                  |                 |                                   |
> >                                  |                 |                                   |
> >                                  |                 |                                   |
> >                                  |                 |                                   |
> >                   +--------------|--------|--------|--------|--------|--------|--------|----------------------------------------------+
> >                   |              |        |        |        |        |        |        |                                              |
> >  Completion Queue |              |        |        |        |        |        |        |                                              |
> >                   |              |        |        |        |        |        |        |                                              |
> >                   +--------------|--------|--------|--------|--------|--------|--------|----------------------------------------------+
> >                                  |                 |                                   |
> >                                  |                 |                                   |
> >                                  |-----------------|                                   |
> >                                   A) T1 syscall    |                                   |
> >                                   writes 2         |                                   |
> >                                   descriptors      |-----------------------------------|
> >                                                     B) T2 syscall writes 4 descriptors
> >
> 
> Hi ALL,
> 
> Since Maciej posted a related patch to fix this issue, it took me a
> little while to trace back to this thread. So here we are.
> 
> >                  Notes:
> >                  1) T1 and T2 AF_XDP sockets are two different sockets,
> >                     __xsk_generic_xmit will obtain two different mutexes.
> >                  2) T1 and T2 can be executed simultaneously, there is no
> >                     critical section whatsoever between them.
> >                  3) T1 and T2 will obtain Completion Queue Lock for acquire + write,
> >                     only slot acquire + write are under lock.
> >                  4) T1 and T2 completion (skb destructor)
> >                     doesn't need to be the same order as A) and B).
> >                  5) What if T1 fails after T2 acquires slots?
> 
> What does it mean by 'fails'. Could you point out the accurate
> function you said?
> 
> >                     cached_writer will be decreased by 2, T2 will
> >                     submit failed descriptors of T1 (they shall be
> >                     retransmitted in next TX).
> >                     Submission of writer will move writer by 4 slots
> >                     2 of these slots have failed T1 values. Last two
> >                     slots of T2 will be missing, descriptor leak.
> 
> I wonder why the leak problem happens? IIUC, in the
> __xsk_generic_xmit() + copy mode, xsk only tries to send the
> descriptor from its own tx ring to the driver, like virtio_net as an
> example. As you said, there are two xsks running in parallel. Why
> could T2 send the descriptors that T1 puts into the completion queue?
> __dev_direct_xmit() only passes the @skb that is built based on the
> addr from per xsk tx ring.

 I admit it is non-trivial case.

Per my understanding before, based on Eryk's example, if T1 failed xmit
and reduced the cached_prod, T2 in its skb destructor would release two T1
umem addresses and two T2 addrs instead of 4 T2 addrs.

Putting this aside though, we had *correct* behavior before xsk
multi-buffer support, we should not let that change make it into kernel in
the first place. Hence my motivation to restore it.$

> 
> Here are some maps related to the process you talked about:
> case 1)
> // T1 writes 2 descs in cq
> [--1--][--2--][-null-][-null-][-null-][-null-][-null-]
>                       |
>                       cached_prod
> 
> // T1 fails because of NETDEV_TX_BUSY, and cq.cached_prod is decreased by 2.
> [-null-][-null-][-null-][-null-][-null-][-null-][-null-]
>      |
>      cached_prod
> 
> // T2 starts to write at the first unused descs
> [--1--][--2--][--3--][--4--][-null-][-null-][-null-]
>                                         |
>                                         cached_prod
> So why can T2 send out the descs belonging to T1? In
> __xsk_generic_xmit(), xsk_cq_reserve_addr_locked() initialises the
> addr of acquired desc so it overwrites the invalid one previously
> owned by T1. The addr is from per xsk tx ring... I'm lost. Could you
> please share the detailed/key functions to shed more lights on this?
> Thanks in advance.

Take another look at Eryk's example. The case he was providing was when t1
produced smaller amount of addrs followed by t2 with bigger count. Then
due to t1 failure, t2 was providing addrs produced by t1.

Your example talks about immediate failure of t1 whereas Eryk talked
about:
1. t1 produces addrs to cq
2. t2 produces addrs to cq
3. t2 starts xmit
4. t1 fails for some reason down in __xsk_generic_xmit()
4a. t1 reduces cached_prod
5. t2 completes, updates global state of cq's producer and exposing addrs
   produced by t1 and misses part of addrs produced by t2

> 
> I know you're not running on the (virtual) nic actually, but I still
> want to know the possibility of the issue with normal end-to-end
> transmission. In the virtio_net driver, __dev_direct_xmit() returns
> BUSY only if the BQL takes effect, so your case might not happen here?
> The reason why I asked is that I have a similar use case with
> virtio_net and I am trying to understand whether it can happen in the
> future.
> 
> Thanks,
> Jason
> 
> 
> >                  6) What if T2 completes before T1? writer will be
> >                     moved by 4 slots. 2 of them are slots filled by T1.
> >                     T2 will complete 2 own slots and 2 slots of T1, It's bad.
> >                     T1 will complete last 2 slots of T2, also bad.
> >
> > This out-of-order completion can effectively cause User-space <-> Kernel-space
> > data race. This patch solves that, by only acquiring cached_writer first and
> > do the completion (sumission (write + increase writer)) after. This is the only
> > way to make that bulletproof for multithreaded access, failures and
> > out-of-order skb completions.
> >
> > > This is definitely a no-go (sk_buff and skb_shared_info space is
> > > precious).
> >
> > Okay so where should I store It? Can you give me some advice?
> >
> > I left that there, because there is every information related to
> > skb desctruction. Additionally this is the only place in skb related
> > code that defines anything related to xsk: metadata, number of descriptors.
> > SKBUFF doesn't. I need to hold this information somewhere, and skbuff or
> > skb_shared_info are the only place I can store it. This need to be invariant
> > across all skb fragments, and be released after skb completes.
> >

Re: Re: [PATCH bpf v2] xsk: Fix out of order segment free in __xsk_generic_xmit()

[Jason Xing]

On Fri, Jul 4, 2025 at 8:35 PM Maciej Fijalkowski
<maciej.fijalkowski@intel.com> wrote:
>
> On Fri, Jul 04, 2025 at 07:37:22AM +0800, Jason Xing wrote:
> > On Mon, Jun 2, 2025 at 5:28 PM Eryk Kubanski
> > <e.kubanski@partner.samsung.com> wrote:
> > >
> > > > I'm not sure I understand what's the issue here. If you're using the
> > > > same XSK from different CPUs, you should take care of the ordering
> > > > yourself on the userspace side?
> > >
> > > It's not a problem with user-space Completion Queue READER side.
> > > Im talking exclusively about kernel-space Completion Queue WRITE side.
> > >
> > > This problem can occur when multiple sockets are bound to the same
> > > umem, device, queue id. In this situation Completion Queue is shared.
> > > This means it can be accessed by multiple threads on kernel-side.
> > > Any use is indeed protected by spinlock, however any write sequence
> > > (Acquire write slot as writer, write to slot, submit write slot to reader)
> > > isn't atomic in any way and it's possible to submit not-yet-sent packet
> > > descriptors back to user-space as TX completed.
> > >
> > > Up untill now, all write-back operations had two phases, each phase
> > > locks the spinlock and unlocks it:
> > > 1) Acquire slot + Write descriptor (increase cached-writer by N + write values)
> > > 2) Submit slot to the reader (increase writer by N)
> > >
> > > Slot submission was solely based on the timing. Let's consider situation,
> > > where two different threads issue a syscall for two different AF_XDP sockets
> > > that are bound to the same umem, dev, queue-id.
> > >
> > > AF_XDP setup:
> > >
> > >                              kernel-space
> > >
> > >            Write   Read
> > >             +--+   +--+
> > >             |  |   |  |
> > >             |  |   |  |
> > >             |  |   |  |
> > >  Completion |  |   |  | Fill
> > >  Queue      |  |   |  | Queue
> > >             |  |   |  |
> > >             |  |   |  |
> > >             |  |   |  |
> > >             |  |   |  |
> > >             +--+   +--+
> > >             Read   Write
> > >                              user-space
> > >
> > >
> > >    +--------+         +--------+
> > >    | AF_XDP |         | AF_XDP |
> > >    +--------+         +--------+
> > >
> > >
> > >
> > >
> > >
> > > Possible out-of-order scenario:
> > >
> > >
> > >                               writer         cached_writer1                      cached_writer2
> > >                                  |                 |                                   |
> > >                                  |                 |                                   |
> > >                                  |                 |                                   |
> > >                                  |                 |                                   |
> > >                   +--------------|--------|--------|--------|--------|--------|--------|----------------------------------------------+
> > >                   |              |        |        |        |        |        |        |                                              |
> > >  Completion Queue |              |        |        |        |        |        |        |                                              |
> > >                   |              |        |        |        |        |        |        |                                              |
> > >                   +--------------|--------|--------|--------|--------|--------|--------|----------------------------------------------+
> > >                                  |                 |                                   |
> > >                                  |                 |                                   |
> > >                                  |-----------------|                                   |
> > >                                   A) T1 syscall    |                                   |
> > >                                   writes 2         |                                   |
> > >                                   descriptors      |-----------------------------------|
> > >                                                     B) T2 syscall writes 4 descriptors
> > >
> >
> > Hi ALL,
> >
> > Since Maciej posted a related patch to fix this issue, it took me a
> > little while to trace back to this thread. So here we are.
> >
> > >                  Notes:
> > >                  1) T1 and T2 AF_XDP sockets are two different sockets,
> > >                     __xsk_generic_xmit will obtain two different mutexes.
> > >                  2) T1 and T2 can be executed simultaneously, there is no
> > >                     critical section whatsoever between them.
> > >                  3) T1 and T2 will obtain Completion Queue Lock for acquire + write,
> > >                     only slot acquire + write are under lock.
> > >                  4) T1 and T2 completion (skb destructor)
> > >                     doesn't need to be the same order as A) and B).
> > >                  5) What if T1 fails after T2 acquires slots?
> >
> > What does it mean by 'fails'. Could you point out the accurate
> > function you said?
> >
> > >                     cached_writer will be decreased by 2, T2 will
> > >                     submit failed descriptors of T1 (they shall be
> > >                     retransmitted in next TX).
> > >                     Submission of writer will move writer by 4 slots
> > >                     2 of these slots have failed T1 values. Last two
> > >                     slots of T2 will be missing, descriptor leak.
> >
> > I wonder why the leak problem happens? IIUC, in the
> > __xsk_generic_xmit() + copy mode, xsk only tries to send the
> > descriptor from its own tx ring to the driver, like virtio_net as an
> > example. As you said, there are two xsks running in parallel. Why
> > could T2 send the descriptors that T1 puts into the completion queue?
> > __dev_direct_xmit() only passes the @skb that is built based on the
> > addr from per xsk tx ring.
>
>  I admit it is non-trivial case.
>
> Per my understanding before, based on Eryk's example, if T1 failed xmit
> and reduced the cached_prod, T2 in its skb destructor would release two T1
> umem addresses and two T2 addrs instead of 4 T2 addrs.
>
> Putting this aside though, we had *correct* behavior before xsk
> multi-buffer support, we should not let that change make it into kernel in
> the first place. Hence my motivation to restore it.$
>
> >
> > Here are some maps related to the process you talked about:
> > case 1)
> > // T1 writes 2 descs in cq
> > [--1--][--2--][-null-][-null-][-null-][-null-][-null-]
> >                       |
> >                       cached_prod
> >
> > // T1 fails because of NETDEV_TX_BUSY, and cq.cached_prod is decreased by 2.
> > [-null-][-null-][-null-][-null-][-null-][-null-][-null-]
> >      |
> >      cached_prod
> >
> > // T2 starts to write at the first unused descs
> > [--1--][--2--][--3--][--4--][-null-][-null-][-null-]
> >                                         |
> >                                         cached_prod
> > So why can T2 send out the descs belonging to T1? In
> > __xsk_generic_xmit(), xsk_cq_reserve_addr_locked() initialises the
> > addr of acquired desc so it overwrites the invalid one previously
> > owned by T1. The addr is from per xsk tx ring... I'm lost. Could you
> > please share the detailed/key functions to shed more lights on this?
> > Thanks in advance.
>
> Take another look at Eryk's example. The case he was providing was when t1
> produced smaller amount of addrs followed by t2 with bigger count. Then
> due to t1 failure, t2 was providing addrs produced by t1.
>
> Your example talks about immediate failure of t1 whereas Eryk talked
> about:
> 1. t1 produces addrs to cq
> 2. t2 produces addrs to cq
> 3. t2 starts xmit
> 4. t1 fails for some reason down in __xsk_generic_xmit()
> 4a. t1 reduces cached_prod
> 5. t2 completes, updates global state of cq's producer and exposing addrs
>    produced by t1 and misses part of addrs produced by t2

Wow, thanks for sharing your understanding on this. It's very clear
and easy to understand to me.

Thanks,
Jason

Re: [PATCH bpf v2] xsk: Fix out of order segment free in __xsk_generic_xmit()

[kernel test robot]

Hello,

kernel test robot noticed a 16.6% regression of hackbench.throughput on:


commit: 2adc2445a5ae93efed1e2e6646a37a3afff8c0e9 ("[PATCH bpf v2] xsk: Fix out of order segment free in __xsk_generic_xmit()")
url: https://github.com/intel-lab-lkp/linux/commits/e-kubanski/xsk-Fix-out-of-order-segment-free-in-__xsk_generic_xmit/20250530-183723
base: https://git.kernel.org/cgit/linux/kernel/git/bpf/bpf.git master
patch link: https://lore.kernel.org/all/20250530103456.53564-1-e.kubanski@partner.samsung.com/
patch subject: [PATCH bpf v2] xsk: Fix out of order segment free in __xsk_generic_xmit()

testcase: hackbench
config: x86_64-rhel-9.4
compiler: gcc-12
test machine: 128 threads 2 sockets Intel(R) Xeon(R) Gold 6338 CPU @ 2.00GHz (Ice Lake) with 256G memory
parameters:

	nr_threads: 50%
	iterations: 4
	mode: threads
	ipc: socket
	cpufreq_governor: performance


In addition to that, the commit also has significant impact on the following tests:

+------------------+---------------------------------------------------------------------------------------------+
| testcase: change | netperf: netperf.Throughput_Mbps 93440.1% improvement                                       |
| test machine     | 192 threads 2 sockets Intel(R) Xeon(R) 6740E  CPU @ 2.4GHz (Sierra Forest) with 256G memory |
| test parameters  | cluster=cs-localhost                                                                        |
|                  | cpufreq_governor=performance                                                                |
|                  | ip=ipv4                                                                                     |
|                  | nr_threads=50%                                                                              |
|                  | runtime=300s                                                                                |
|                  | test=SCTP_STREAM                                                                            |
+------------------+---------------------------------------------------------------------------------------------+


If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <oliver.sang@intel.com>
| Closes: https://lore.kernel.org/oe-lkp/202506042255.a3161554-lkp@intel.com


Details are as below:
-------------------------------------------------------------------------------------------------->


The kernel config and materials to reproduce are available at:
https://download.01.org/0day-ci/archive/20250604/202506042255.a3161554-lkp@intel.com

=========================================================================================
compiler/cpufreq_governor/ipc/iterations/kconfig/mode/nr_threads/rootfs/tbox_group/testcase:
  gcc-12/performance/socket/4/x86_64-rhel-9.4/threads/50%/debian-12-x86_64-20240206.cgz/lkp-icl-2sp2/hackbench

commit: 
  90b83efa67 ("Merge tag 'bpf-next-6.16' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next")
  2adc2445a5 ("xsk: Fix out of order segment free in __xsk_generic_xmit()")

90b83efa6701656e 2adc2445a5ae93efed1e2e6646a 
---------------- --------------------------- 
         %stddev     %change         %stddev
             \          |                \  
      8018           -11.4%       7101        sched_debug.cpu.curr->pid.avg
    195.95           +14.6%     224.54        uptime.boot
      0.01           -16.8%       0.01        vmstat.swap.so
    764179 ±  3%      -8.2%     701708        vmstat.system.in
      2.13 ± 13%      -0.5        1.63 ±  2%  mpstat.cpu.all.idle%
      0.53            -0.1        0.44        mpstat.cpu.all.irq%
      7.09            -1.1        5.95        mpstat.cpu.all.usr%
    558.00 ±  9%     +31.5%     733.67 ± 26%  perf-c2c.DRAM.local
     23177 ±  6%     +17.3%      27181 ±  6%  perf-c2c.DRAM.remote
    161171            +3.4%     166696        perf-c2c.HITM.total
     92761            +4.0%      96435        proc-vmstat.nr_slab_reclaimable
   3143593 ±  4%      +9.5%    3442455 ±  6%  proc-vmstat.nr_unaccepted
   2154280 ±  8%     +19.0%    2563937 ± 11%  proc-vmstat.numa_interleave
   3260150 ±  6%     +63.8%    5339352 ±  6%  proc-vmstat.pgalloc_dma32
     34526 ±  3%     +30.6%      45105 ± 18%  proc-vmstat.pgrefill
   1700255          +119.7%    3735986 ±  2%  proc-vmstat.pgskip_device
    423595           -16.6%     353120        hackbench.throughput
    418312           -17.0%     347114        hackbench.throughput_avg
    423595           -16.6%     353120        hackbench.throughput_best
    408057           -17.1%     338325        hackbench.throughput_worst
    144.25           +20.3%     173.60        hackbench.time.elapsed_time
    144.25           +20.3%     173.60        hackbench.time.elapsed_time.max
 1.098e+08 ±  2%     +17.6%  1.291e+08        hackbench.time.involuntary_context_switches
     81915            +1.7%      83317        hackbench.time.minor_page_faults
     16768           +22.4%      20519        hackbench.time.system_time
 4.043e+08 ±  4%     +24.1%  5.016e+08        hackbench.time.voluntary_context_switches
 4.874e+10           -11.8%  4.301e+10        perf-stat.i.branch-instructions
      0.45            +0.1        0.54        perf-stat.i.branch-miss-rate%
  2.13e+08            +5.9%  2.255e+08        perf-stat.i.branch-misses
      7.45 ±  2%      +0.2        7.69        perf-stat.i.cache-miss-rate%
 1.501e+08 ±  4%     -16.6%  1.253e+08        perf-stat.i.cache-misses
 2.054e+09           -19.6%  1.652e+09        perf-stat.i.cache-references
      1.38           +14.9%       1.59        perf-stat.i.cpi
 3.224e+11            +1.3%  3.265e+11        perf-stat.i.cpu-cycles
    404652 ±  3%     +12.2%     454021        perf-stat.i.cpu-migrations
      2182 ±  4%     +20.8%       2635        perf-stat.i.cycles-between-cache-misses
 2.333e+11           -11.9%  2.054e+11        perf-stat.i.instructions
      0.73           -12.8%       0.63        perf-stat.i.ipc
      0.44            +0.1        0.52        perf-stat.overall.branch-miss-rate%
      7.31 ±  2%      +0.3        7.58        perf-stat.overall.cache-miss-rate%
      1.38           +15.0%       1.59        perf-stat.overall.cpi
      2151 ±  4%     +21.2%       2607        perf-stat.overall.cycles-between-cache-misses
      0.72           -13.0%       0.63        perf-stat.overall.ipc
 4.841e+10           -11.7%  4.277e+10        perf-stat.ps.branch-instructions
 2.114e+08            +6.0%  2.241e+08        perf-stat.ps.branch-misses
 1.491e+08 ±  4%     -16.5%  1.245e+08        perf-stat.ps.cache-misses
 2.039e+09           -19.5%  1.642e+09        perf-stat.ps.cache-references
 3.201e+11            +1.4%  3.246e+11        perf-stat.ps.cpu-cycles
    401515 ±  3%     +12.3%     450975        perf-stat.ps.cpu-migrations
 2.317e+11           -11.8%  2.042e+11        perf-stat.ps.instructions
 3.368e+13            +6.0%  3.569e+13        perf-stat.total.instructions
      1.64 ±205%     -98.2%       0.03 ±183%  perf-sched.sch_delay.avg.ms.__cond_resched.exit_mmap.__mmput.exit_mm.do_exit
     65.76 ± 92%     -73.9%      17.16 ± 93%  perf-sched.sch_delay.avg.ms.do_wait.kernel_wait4.do_syscall_64.entry_SYSCALL_64_after_hwframe
      5.76 ± 75%     -73.3%       1.54 ± 42%  perf-sched.sch_delay.avg.ms.irqentry_exit_to_user_mode.asm_sysvec_reschedule_ipi.[unknown].[unknown]
    100.68 ±112%    +329.5%     432.45 ± 77%  perf-sched.sch_delay.max.ms.__cond_resched.__alloc_frozen_pages_noprof.alloc_pages_mpol.folio_alloc_mpol_noprof.shmem_alloc_folio
      3.19 ±212%     -99.0%       0.03 ±183%  perf-sched.sch_delay.max.ms.__cond_resched.exit_mmap.__mmput.exit_mm.do_exit
      1402 ± 35%     -62.6%     524.30 ± 93%  perf-sched.sch_delay.max.ms.do_wait.kernel_wait4.do_syscall_64.entry_SYSCALL_64_after_hwframe
      5.57 ± 14%     -88.9%       0.62 ±223%  perf-sched.wait_and_delay.avg.ms.__cond_resched.__kmalloc_node_track_caller_noprof.kmalloc_reserve.__alloc_skb.alloc_skb_with_frags
      4.98 ± 12%    -100.0%       0.00        perf-sched.wait_and_delay.avg.ms.__cond_resched.kmem_cache_alloc_node_noprof.__alloc_skb.alloc_skb_with_frags.sock_alloc_send_pskb
    224.22 ± 65%    -100.0%       0.00        perf-sched.wait_and_delay.avg.ms.do_task_dead.do_exit.__x64_sys_exit.x64_sys_call.do_syscall_64
    475.81 ± 41%     -89.0%      52.54 ± 81%  perf-sched.wait_and_delay.avg.ms.schedule_hrtimeout_range_clock.ep_poll.do_epoll_wait.__x64_sys_epoll_wait
      5.33 ±124%    +628.1%      38.83 ± 41%  perf-sched.wait_and_delay.count.__cond_resched.__kmalloc_node_noprof.alloc_slab_obj_exts.allocate_slab.___slab_alloc
     12463 ± 15%     -84.9%       1881 ±223%  perf-sched.wait_and_delay.count.__cond_resched.__kmalloc_node_track_caller_noprof.kmalloc_reserve.__alloc_skb.alloc_skb_with_frags
     23237 ± 16%    -100.0%       0.00        perf-sched.wait_and_delay.count.__cond_resched.kmem_cache_alloc_node_noprof.__alloc_skb.alloc_skb_with_frags.sock_alloc_send_pskb
     13.33 ±216%   +1085.0%     158.00 ± 54%  perf-sched.wait_and_delay.count.devkmsg_read.vfs_read.ksys_read.do_syscall_64
     14.17 ± 61%    -100.0%       0.00        perf-sched.wait_and_delay.count.do_task_dead.do_exit.__x64_sys_exit.x64_sys_call.do_syscall_64
    610.67 ± 21%     -25.9%     452.67 ± 27%  perf-sched.wait_and_delay.count.irqentry_exit_to_user_mode.asm_sysvec_apic_timer_interrupt.[unknown].[unknown]
     24.50 ±157%    +597.3%     170.83 ± 37%  perf-sched.wait_and_delay.count.schedule_hrtimeout_range_clock.ep_poll.do_epoll_wait.__x64_sys_epoll_wait
      1018 ± 33%     -88.8%     113.91 ±223%  perf-sched.wait_and_delay.max.ms.__cond_resched.__kmalloc_node_track_caller_noprof.kmalloc_reserve.__alloc_skb.alloc_skb_with_frags
      1165 ± 29%    -100.0%       0.00        perf-sched.wait_and_delay.max.ms.__cond_resched.kmem_cache_alloc_node_noprof.__alloc_skb.alloc_skb_with_frags.sock_alloc_send_pskb
      1285 ± 70%    -100.0%       0.00        perf-sched.wait_and_delay.max.ms.do_task_dead.do_exit.__x64_sys_exit.x64_sys_call.do_syscall_64
      1.64 ±205%     -98.2%       0.03 ±183%  perf-sched.wait_time.avg.ms.__cond_resched.exit_mmap.__mmput.exit_mm.do_exit
      7.82 ±216%     -99.1%       0.07 ± 70%  perf-sched.wait_time.avg.ms.__cond_resched.zap_pte_range.zap_pmd_range.isra.0
    224.22 ± 65%    -100.0%       0.00        perf-sched.wait_time.avg.ms.do_task_dead.do_exit.__x64_sys_exit.x64_sys_call.do_syscall_64
    473.32 ± 42%     -90.2%      46.32 ± 78%  perf-sched.wait_time.avg.ms.schedule_hrtimeout_range_clock.ep_poll.do_epoll_wait.__x64_sys_epoll_wait
    100.68 ±112%    +329.5%     432.45 ± 77%  perf-sched.wait_time.max.ms.__cond_resched.__alloc_frozen_pages_noprof.alloc_pages_mpol.folio_alloc_mpol_noprof.shmem_alloc_folio
      3.19 ±212%     -99.0%       0.03 ±183%  perf-sched.wait_time.max.ms.__cond_resched.exit_mmap.__mmput.exit_mm.do_exit
    169.23 ±219%     -99.9%       0.24 ± 65%  perf-sched.wait_time.max.ms.__cond_resched.zap_pte_range.zap_pmd_range.isra.0
      1285 ± 70%    -100.0%       0.00        perf-sched.wait_time.max.ms.do_task_dead.do_exit.__x64_sys_exit.x64_sys_call.do_syscall_64
      9.37 ±  2%      -3.6        5.80        perf-profile.calltrace.cycles-pp.kmem_cache_free.unix_stream_read_generic.unix_stream_recvmsg.sock_recvmsg.sock_read_iter
      5.90 ±  4%      -2.2        3.66        perf-profile.calltrace.cycles-pp.kmem_cache_alloc_node_noprof.__alloc_skb.alloc_skb_with_frags.sock_alloc_send_pskb.unix_stream_sendmsg
      2.45 ± 10%      -1.7        0.76        perf-profile.calltrace.cycles-pp.___slab_alloc.kmem_cache_alloc_node_noprof.__alloc_skb.alloc_skb_with_frags.sock_alloc_send_pskb
     47.96            -1.3       46.61        perf-profile.calltrace.cycles-pp.write
      6.20            -1.2        4.99        perf-profile.calltrace.cycles-pp.sock_def_readable.unix_stream_sendmsg.sock_write_iter.vfs_write.ksys_write
      4.58 ±  2%      -0.9        3.71        perf-profile.calltrace.cycles-pp.__wake_up_sync_key.sock_def_readable.unix_stream_sendmsg.sock_write_iter.vfs_write
      6.97            -0.8        6.13        perf-profile.calltrace.cycles-pp.unix_stream_read_actor.unix_stream_read_generic.unix_stream_recvmsg.sock_recvmsg.sock_read_iter
      6.88            -0.8        6.04        perf-profile.calltrace.cycles-pp.skb_copy_datagram_iter.unix_stream_read_actor.unix_stream_read_generic.unix_stream_recvmsg.sock_recvmsg
      6.70 ±  2%      -0.8        5.90        perf-profile.calltrace.cycles-pp.__skb_datagram_iter.skb_copy_datagram_iter.unix_stream_read_actor.unix_stream_read_generic.unix_stream_recvmsg
      3.73 ±  4%      -0.7        3.04        perf-profile.calltrace.cycles-pp.__wake_up_common.__wake_up_sync_key.sock_def_readable.unix_stream_sendmsg.sock_write_iter
      3.60 ±  4%      -0.7        2.93        perf-profile.calltrace.cycles-pp.autoremove_wake_function.__wake_up_common.__wake_up_sync_key.sock_def_readable.unix_stream_sendmsg
      3.54 ±  4%      -0.7        2.89        perf-profile.calltrace.cycles-pp.try_to_wake_up.autoremove_wake_function.__wake_up_common.__wake_up_sync_key.sock_def_readable
      2.89 ±  5%      -0.6        2.25        perf-profile.calltrace.cycles-pp._raw_spin_lock.unix_stream_sendmsg.sock_write_iter.vfs_write.ksys_write
      3.40 ±  2%      -0.6        2.80        perf-profile.calltrace.cycles-pp.__memcg_slab_free_hook.kmem_cache_free.unix_stream_read_generic.unix_stream_recvmsg.sock_recvmsg
      2.62 ±  7%      -0.6        2.06 ±  4%  perf-profile.calltrace.cycles-pp.fdget_pos.ksys_write.do_syscall_64.entry_SYSCALL_64_after_hwframe.write
      2.94            -0.5        2.42        perf-profile.calltrace.cycles-pp.skb_copy_datagram_from_iter.unix_stream_sendmsg.sock_write_iter.vfs_write.ksys_write
      3.15 ±  4%      -0.5        2.67        perf-profile.calltrace.cycles-pp.schedule_timeout.unix_stream_read_generic.unix_stream_recvmsg.sock_recvmsg.sock_read_iter
      3.20 ±  2%      -0.5        2.72        perf-profile.calltrace.cycles-pp.skb_release_head_state.consume_skb.unix_stream_read_generic.unix_stream_recvmsg.sock_recvmsg
      3.12 ±  5%      -0.5        2.65        perf-profile.calltrace.cycles-pp.schedule.schedule_timeout.unix_stream_read_generic.unix_stream_recvmsg.sock_recvmsg
      3.09 ±  4%      -0.5        2.62        perf-profile.calltrace.cycles-pp.__schedule.schedule.schedule_timeout.unix_stream_read_generic.unix_stream_recvmsg
      3.05 ±  2%      -0.4        2.60        perf-profile.calltrace.cycles-pp.unix_destruct_scm.skb_release_head_state.consume_skb.unix_stream_read_generic.unix_stream_recvmsg
      2.97 ±  2%      -0.4        2.54        perf-profile.calltrace.cycles-pp._copy_to_iter.__skb_datagram_iter.skb_copy_datagram_iter.unix_stream_read_actor.unix_stream_read_generic
      2.46            -0.4        2.03        perf-profile.calltrace.cycles-pp.entry_SYSCALL_64.write
      2.44            -0.4        2.02        perf-profile.calltrace.cycles-pp.entry_SYSCALL_64.read
      2.84 ±  2%      -0.4        2.42        perf-profile.calltrace.cycles-pp.sock_wfree.unix_destruct_scm.skb_release_head_state.consume_skb.unix_stream_read_generic
      1.72 ±  3%      -0.4        1.32        perf-profile.calltrace.cycles-pp.skb_set_owner_w.sock_alloc_send_pskb.unix_stream_sendmsg.sock_write_iter.vfs_write
      1.90            -0.4        1.51        perf-profile.calltrace.cycles-pp.clear_bhb_loop.write
      1.30            -0.4        0.91        perf-profile.calltrace.cycles-pp.__slab_free.kfree.skb_release_data.consume_skb.unix_stream_read_generic
      2.28 ±  2%      -0.3        1.94        perf-profile.calltrace.cycles-pp.__memcg_slab_post_alloc_hook.kmem_cache_alloc_node_noprof.__alloc_skb.alloc_skb_with_frags.sock_alloc_send_pskb
      1.86            -0.3        1.52        perf-profile.calltrace.cycles-pp.clear_bhb_loop.read
      3.08            -0.3        2.78        perf-profile.calltrace.cycles-pp.__memcg_slab_free_hook.kfree.skb_release_data.consume_skb.unix_stream_read_generic
      0.61 ±  6%      -0.3        0.33 ± 70%  perf-profile.calltrace.cycles-pp.dequeue_entity.dequeue_entities.dequeue_task_fair.try_to_block_task.__schedule
      3.12            -0.3        2.86        perf-profile.calltrace.cycles-pp.simple_copy_to_iter.__skb_datagram_iter.skb_copy_datagram_iter.unix_stream_read_actor.unix_stream_read_generic
      1.62 ±  6%      -0.3        1.36 ±  2%  perf-profile.calltrace.cycles-pp.skb_queue_tail.unix_stream_sendmsg.sock_write_iter.vfs_write.ksys_write
      1.28            -0.2        1.05        perf-profile.calltrace.cycles-pp.__check_object_size.skb_copy_datagram_from_iter.unix_stream_sendmsg.sock_write_iter.vfs_write
      2.91 ±  2%      -0.2        2.68        perf-profile.calltrace.cycles-pp.__check_object_size.simple_copy_to_iter.__skb_datagram_iter.skb_copy_datagram_iter.unix_stream_read_actor
      1.70 ±  4%      -0.2        1.47        perf-profile.calltrace.cycles-pp.ttwu_do_activate.try_to_wake_up.autoremove_wake_function.__wake_up_common.__wake_up_sync_key
      1.13            -0.2        0.92        perf-profile.calltrace.cycles-pp.__slab_free.kmem_cache_free.unix_stream_read_generic.unix_stream_recvmsg.sock_recvmsg
      1.24            -0.2        1.04        perf-profile.calltrace.cycles-pp._copy_from_iter.skb_copy_datagram_from_iter.unix_stream_sendmsg.sock_write_iter.vfs_write
      0.98 ±  6%      -0.2        0.78 ±  8%  perf-profile.calltrace.cycles-pp.fdget_pos.ksys_read.do_syscall_64.entry_SYSCALL_64_after_hwframe.read
      1.20 ±  6%      -0.2        1.00        perf-profile.calltrace.cycles-pp.try_to_block_task.__schedule.schedule.schedule_timeout.unix_stream_read_generic
      1.12 ±  6%      -0.2        0.93        perf-profile.calltrace.cycles-pp.dequeue_entities.dequeue_task_fair.try_to_block_task.__schedule.schedule
      1.16 ±  5%      -0.2        0.97        perf-profile.calltrace.cycles-pp.dequeue_task_fair.try_to_block_task.__schedule.schedule.schedule_timeout
      0.84 ±  5%      -0.2        0.66        perf-profile.calltrace.cycles-pp._raw_spin_lock_irqsave.__wake_up_sync_key.sock_def_readable.unix_stream_sendmsg.sock_write_iter
      1.42 ±  4%      -0.2        1.24        perf-profile.calltrace.cycles-pp.enqueue_task.ttwu_do_activate.try_to_wake_up.autoremove_wake_function.__wake_up_common
      1.35 ±  4%      -0.2        1.18        perf-profile.calltrace.cycles-pp.enqueue_task_fair.enqueue_task.ttwu_do_activate.try_to_wake_up.autoremove_wake_function
      0.78 ±  6%      -0.2        0.61        perf-profile.calltrace.cycles-pp.native_queued_spin_lock_slowpath._raw_spin_lock_irqsave.__wake_up_sync_key.sock_def_readable.unix_stream_sendmsg
      0.71            -0.1        0.59        perf-profile.calltrace.cycles-pp.mutex_lock.unix_stream_read_generic.unix_stream_recvmsg.sock_recvmsg.sock_read_iter
      0.66 ±  2%      -0.1        0.54        perf-profile.calltrace.cycles-pp.check_heap_object.__check_object_size.skb_copy_datagram_from_iter.unix_stream_sendmsg.sock_write_iter
      2.15 ±  2%      -0.1        2.04        perf-profile.calltrace.cycles-pp.check_heap_object.__check_object_size.simple_copy_to_iter.__skb_datagram_iter.skb_copy_datagram_iter
      0.81 ±  4%      -0.1        0.71        perf-profile.calltrace.cycles-pp.enqueue_entity.enqueue_task_fair.enqueue_task.ttwu_do_activate.try_to_wake_up
      0.93 ±  3%      -0.1        0.83        perf-profile.calltrace.cycles-pp.__pick_next_task.__schedule.schedule.schedule_timeout.unix_stream_read_generic
      0.60 ±  6%      -0.1        0.51        perf-profile.calltrace.cycles-pp.exit_to_user_mode_loop.do_syscall_64.entry_SYSCALL_64_after_hwframe.read
      0.90 ±  3%      -0.1        0.81        perf-profile.calltrace.cycles-pp.pick_next_task_fair.__pick_next_task.__schedule.schedule.schedule_timeout
      2.57            -0.1        2.48        perf-profile.calltrace.cycles-pp.__memcg_slab_post_alloc_hook.__kmalloc_node_track_caller_noprof.kmalloc_reserve.__alloc_skb.alloc_skb_with_frags
      0.70            -0.1        0.64        perf-profile.calltrace.cycles-pp.mod_objcg_state.__memcg_slab_free_hook.kmem_cache_free.unix_stream_read_generic.unix_stream_recvmsg
      0.75            -0.1        0.69        perf-profile.calltrace.cycles-pp.mod_objcg_state.__memcg_slab_free_hook.kfree.skb_release_data.consume_skb
      0.58            -0.0        0.54        perf-profile.calltrace.cycles-pp.mod_objcg_state.__memcg_slab_post_alloc_hook.kmem_cache_alloc_node_noprof.__alloc_skb.alloc_skb_with_frags
      0.73            -0.0        0.69        perf-profile.calltrace.cycles-pp.unix_write_space.sock_wfree.unix_destruct_scm.skb_release_head_state.consume_skb
      0.78            +0.2        0.93        perf-profile.calltrace.cycles-pp.obj_cgroup_charge.__memcg_slab_post_alloc_hook.__kmalloc_node_track_caller_noprof.kmalloc_reserve.__alloc_skb
     37.84            +0.6       38.45        perf-profile.calltrace.cycles-pp.vfs_write.ksys_write.do_syscall_64.entry_SYSCALL_64_after_hwframe.write
     36.76            +0.8       37.56        perf-profile.calltrace.cycles-pp.sock_write_iter.vfs_write.ksys_write.do_syscall_64.entry_SYSCALL_64_after_hwframe
     35.40            +1.1       36.46        perf-profile.calltrace.cycles-pp.unix_stream_sendmsg.sock_write_iter.vfs_write.ksys_write.do_syscall_64
     49.97            +2.0       52.00        perf-profile.calltrace.cycles-pp.read
     44.96            +2.9       47.89        perf-profile.calltrace.cycles-pp.entry_SYSCALL_64_after_hwframe.read
     44.66            +3.0       47.64        perf-profile.calltrace.cycles-pp.do_syscall_64.entry_SYSCALL_64_after_hwframe.read
     42.34            +3.4       45.72        perf-profile.calltrace.cycles-pp.ksys_read.do_syscall_64.entry_SYSCALL_64_after_hwframe.read
     40.65            +3.7       44.36        perf-profile.calltrace.cycles-pp.vfs_read.ksys_read.do_syscall_64.entry_SYSCALL_64_after_hwframe.read
     39.50            +3.9       43.41        perf-profile.calltrace.cycles-pp.sock_read_iter.vfs_read.ksys_read.do_syscall_64.entry_SYSCALL_64_after_hwframe
     38.66            +4.1       42.71        perf-profile.calltrace.cycles-pp.sock_recvmsg.sock_read_iter.vfs_read.ksys_read.do_syscall_64
     38.11            +4.1       42.26        perf-profile.calltrace.cycles-pp.unix_stream_recvmsg.sock_recvmsg.sock_read_iter.vfs_read.ksys_read
     37.67            +4.2       41.89        perf-profile.calltrace.cycles-pp.unix_stream_read_generic.unix_stream_recvmsg.sock_recvmsg.sock_read_iter.vfs_read
     18.28            +4.4       22.69        perf-profile.calltrace.cycles-pp.sock_alloc_send_pskb.unix_stream_sendmsg.sock_write_iter.vfs_write.ksys_write
     15.55 ±  2%      +4.9       20.48        perf-profile.calltrace.cycles-pp.alloc_skb_with_frags.sock_alloc_send_pskb.unix_stream_sendmsg.sock_write_iter.vfs_write
     15.24 ±  2%      +5.0       20.23        perf-profile.calltrace.cycles-pp.__alloc_skb.alloc_skb_with_frags.sock_alloc_send_pskb.unix_stream_sendmsg.sock_write_iter
      2.08 ± 10%      +7.3        9.40 ±  2%  perf-profile.calltrace.cycles-pp.native_queued_spin_lock_slowpath._raw_spin_lock_irqsave.get_partial_node.___slab_alloc.__kmalloc_node_track_caller_noprof
      2.10 ± 10%      +7.3        9.44 ±  2%  perf-profile.calltrace.cycles-pp._raw_spin_lock_irqsave.get_partial_node.___slab_alloc.__kmalloc_node_track_caller_noprof.kmalloc_reserve
      2.36 ±  9%      +7.6        9.93 ±  2%  perf-profile.calltrace.cycles-pp.get_partial_node.___slab_alloc.__kmalloc_node_track_caller_noprof.kmalloc_reserve.__alloc_skb
      7.51 ±  2%      +7.6       15.09        perf-profile.calltrace.cycles-pp.kmalloc_reserve.__alloc_skb.alloc_skb_with_frags.sock_alloc_send_pskb.unix_stream_sendmsg
      6.99 ±  2%      +7.7       14.64        perf-profile.calltrace.cycles-pp.__kmalloc_node_track_caller_noprof.kmalloc_reserve.__alloc_skb.alloc_skb_with_frags.sock_alloc_send_pskb
      2.89 ±  8%      +8.0       10.89 ±  2%  perf-profile.calltrace.cycles-pp.___slab_alloc.__kmalloc_node_track_caller_noprof.kmalloc_reserve.__alloc_skb.alloc_skb_with_frags
     12.34           +10.2       22.53        perf-profile.calltrace.cycles-pp.consume_skb.unix_stream_read_generic.unix_stream_recvmsg.sock_recvmsg.sock_read_iter
      9.02 ±  3%     +10.7       19.71        perf-profile.calltrace.cycles-pp.skb_release_data.consume_skb.unix_stream_read_generic.unix_stream_recvmsg.sock_recvmsg
      8.36 ±  3%     +10.7       19.08        perf-profile.calltrace.cycles-pp.kfree.skb_release_data.consume_skb.unix_stream_read_generic.unix_stream_recvmsg
      3.21 ± 10%     +11.2       14.44 ±  2%  perf-profile.calltrace.cycles-pp.native_queued_spin_lock_slowpath._raw_spin_lock_irqsave.__put_partials.kfree.skb_release_data
      3.30 ± 10%     +11.3       14.61 ±  2%  perf-profile.calltrace.cycles-pp._raw_spin_lock_irqsave.__put_partials.kfree.skb_release_data.consume_skb
      3.44 ± 10%     +11.5       14.89 ±  2%  perf-profile.calltrace.cycles-pp.__put_partials.kfree.skb_release_data.consume_skb.unix_stream_read_generic
      9.43 ±  2%      -3.6        5.84        perf-profile.children.cycles-pp.kmem_cache_free
      5.98 ±  3%      -2.3        3.72        perf-profile.children.cycles-pp.kmem_cache_alloc_node_noprof
     48.56            -1.5       47.11        perf-profile.children.cycles-pp.write
      6.23            -1.2        5.02        perf-profile.children.cycles-pp.sock_def_readable
      6.60            -0.9        5.68        perf-profile.children.cycles-pp.__memcg_slab_free_hook
      4.32 ±  2%      -0.9        3.40        perf-profile.children.cycles-pp._raw_spin_lock
      7.01            -0.8        6.16        perf-profile.children.cycles-pp.unix_stream_read_actor
      4.86 ±  2%      -0.8        4.02        perf-profile.children.cycles-pp.__wake_up_sync_key
      6.91            -0.8        6.08        perf-profile.children.cycles-pp.skb_copy_datagram_iter
      6.76            -0.8        5.95        perf-profile.children.cycles-pp.__skb_datagram_iter
      3.64 ±  6%      -0.8        2.87 ±  5%  perf-profile.children.cycles-pp.fdget_pos
      3.80            -0.7        3.06        perf-profile.children.cycles-pp.clear_bhb_loop
      4.00 ±  3%      -0.7        3.35        perf-profile.children.cycles-pp.__wake_up_common
      3.87 ±  4%      -0.6        3.24        perf-profile.children.cycles-pp.autoremove_wake_function
      3.83 ±  4%      -0.6        3.20        perf-profile.children.cycles-pp.try_to_wake_up
      4.15 ±  3%      -0.6        3.53        perf-profile.children.cycles-pp.__schedule
      2.47            -0.6        1.86        perf-profile.children.cycles-pp.__slab_free
      4.04 ±  3%      -0.6        3.49        perf-profile.children.cycles-pp.schedule
      3.05            -0.5        2.52        perf-profile.children.cycles-pp.entry_SYSCALL_64
      3.00            -0.5        2.49        perf-profile.children.cycles-pp.skb_copy_datagram_from_iter
      4.49            -0.5        3.99        perf-profile.children.cycles-pp.__check_object_size
      3.24 ±  2%      -0.5        2.76        perf-profile.children.cycles-pp.skb_release_head_state
      3.11 ±  2%      -0.5        2.65        perf-profile.children.cycles-pp.unix_destruct_scm
      4.98            -0.4        4.53        perf-profile.children.cycles-pp.__memcg_slab_post_alloc_hook
      3.00 ±  2%      -0.4        2.56        perf-profile.children.cycles-pp._copy_to_iter
      3.51 ±  4%      -0.4        3.08        perf-profile.children.cycles-pp.schedule_timeout
      2.88 ±  2%      -0.4        2.46        perf-profile.children.cycles-pp.sock_wfree
      1.74 ±  3%      -0.4        1.33        perf-profile.children.cycles-pp.skb_set_owner_w
      0.45 ± 26%      -0.4        0.07 ± 10%  perf-profile.children.cycles-pp.common_startup_64
      0.45 ± 26%      -0.4        0.07 ± 10%  perf-profile.children.cycles-pp.cpu_startup_entry
      0.44 ± 26%      -0.4        0.07 ± 10%  perf-profile.children.cycles-pp.do_idle
      0.44 ± 26%      -0.4        0.07 ± 11%  perf-profile.children.cycles-pp.start_secondary
      1.82 ±  2%      -0.3        1.51        perf-profile.children.cycles-pp.its_return_thunk
      0.36 ± 28%      -0.3        0.06 ±  8%  perf-profile.children.cycles-pp.cpuidle_idle_call
      0.34 ± 27%      -0.3        0.04 ± 45%  perf-profile.children.cycles-pp.cpuidle_enter
      0.33 ± 27%      -0.3        0.04 ± 71%  perf-profile.children.cycles-pp.acpi_idle_do_entry
      0.33 ± 27%      -0.3        0.04 ± 71%  perf-profile.children.cycles-pp.acpi_idle_enter
      0.34 ± 27%      -0.3        0.04 ± 45%  perf-profile.children.cycles-pp.cpuidle_enter_state
      0.33 ± 28%      -0.3        0.04 ± 71%  perf-profile.children.cycles-pp.acpi_safe_halt
      0.33 ± 28%      -0.3        0.04 ± 71%  perf-profile.children.cycles-pp.pv_native_safe_halt
      3.18            -0.3        2.90        perf-profile.children.cycles-pp.simple_copy_to_iter
      1.94 ±  3%      -0.3        1.67        perf-profile.children.cycles-pp.ttwu_do_activate
      0.35 ± 16%      -0.3        0.08 ±  5%  perf-profile.children.cycles-pp.asm_sysvec_call_function_single
      1.65 ±  6%      -0.3        1.39 ±  2%  perf-profile.children.cycles-pp.skb_queue_tail
      2.93            -0.2        2.69        perf-profile.children.cycles-pp.check_heap_object
      1.38            -0.2        1.14        perf-profile.children.cycles-pp.entry_SYSRETQ_unsafe_stack
      2.66            -0.2        2.43        perf-profile.children.cycles-pp.mod_objcg_state
      1.72 ±  3%      -0.2        1.50        perf-profile.children.cycles-pp.enqueue_task
      1.27            -0.2        1.06        perf-profile.children.cycles-pp._copy_from_iter
      1.63 ±  3%      -0.2        1.42        perf-profile.children.cycles-pp.enqueue_task_fair
      1.30 ±  5%      -0.2        1.11        perf-profile.children.cycles-pp.try_to_block_task
      1.32 ±  5%      -0.2        1.14        perf-profile.children.cycles-pp.dequeue_entities
      0.64 ± 12%      -0.2        0.46 ±  3%  perf-profile.children.cycles-pp.__switch_to
      1.05 ±  3%      -0.2        0.87        perf-profile.children.cycles-pp.exit_to_user_mode_loop
      0.90            -0.2        0.73        perf-profile.children.cycles-pp.fput
      1.50 ±  2%      -0.2        1.32        perf-profile.children.cycles-pp.__pick_next_task
      0.79 ±  7%      -0.2        0.62        perf-profile.children.cycles-pp.raw_spin_rq_lock_nested
      1.33 ±  4%      -0.2        1.16        perf-profile.children.cycles-pp.dequeue_task_fair
      0.61 ±  4%      -0.2        0.45        perf-profile.children.cycles-pp.select_task_rq
      1.46 ±  2%      -0.2        1.30        perf-profile.children.cycles-pp.pick_next_task_fair
      1.00 ±  3%      -0.1        0.86        perf-profile.children.cycles-pp.update_load_avg
      0.77            -0.1        0.63        perf-profile.children.cycles-pp.__cond_resched
      0.51 ±  3%      -0.1        0.37        perf-profile.children.cycles-pp.select_task_rq_fair
      0.76            -0.1        0.62        perf-profile.children.cycles-pp.mutex_lock
      0.85 ±  4%      -0.1        0.72        perf-profile.children.cycles-pp.update_curr
      0.65            -0.1        0.52        perf-profile.children.cycles-pp.skb_unlink
      0.77            -0.1        0.65 ±  2%  perf-profile.children.cycles-pp.__check_heap_object
      0.61            -0.1        0.49        perf-profile.children.cycles-pp.__build_skb_around
      0.18 ±  7%      -0.1        0.06 ±  9%  perf-profile.children.cycles-pp.sysvec_call_function_single
      0.97 ±  3%      -0.1        0.85        perf-profile.children.cycles-pp.enqueue_entity
      0.74 ±  4%      -0.1        0.63        perf-profile.children.cycles-pp.dequeue_entity
      0.46 ±  3%      -0.1        0.34        perf-profile.children.cycles-pp.prepare_to_wait
      0.61            -0.1        0.50        perf-profile.children.cycles-pp.rw_verify_area
      0.62            -0.1        0.51        perf-profile.children.cycles-pp.entry_SYSCALL_64_safe_stack
      0.88            -0.1        0.78        perf-profile.children.cycles-pp.refill_obj_stock
      0.15 ±  6%      -0.1        0.05        perf-profile.children.cycles-pp.__sysvec_call_function_single
      0.59 ±  3%      -0.1        0.49 ±  2%  perf-profile.children.cycles-pp.__virt_addr_valid
      0.62 ±  3%      -0.1        0.51        perf-profile.children.cycles-pp.syscall_return_via_sysret
      0.21 ±  8%      -0.1        0.11 ±  3%  perf-profile.children.cycles-pp.select_idle_sibling
      0.46            -0.1        0.37        perf-profile.children.cycles-pp.mutex_unlock
      0.55            -0.1        0.46 ±  2%  perf-profile.children.cycles-pp.asm_sysvec_apic_timer_interrupt
      0.50 ±  2%      -0.1        0.41        perf-profile.children.cycles-pp.scm_recv_unix
      0.51 ±  2%      -0.1        0.42 ±  2%  perf-profile.children.cycles-pp.sysvec_apic_timer_interrupt
      0.46 ±  3%      -0.1        0.38        perf-profile.children.cycles-pp.pick_task_fair
      0.44            -0.1        0.36        perf-profile.children.cycles-pp.x64_sys_call
      0.45 ±  2%      -0.1        0.37 ±  3%  perf-profile.children.cycles-pp.__sysvec_apic_timer_interrupt
      0.44 ±  2%      -0.1        0.36 ±  3%  perf-profile.children.cycles-pp.hrtimer_interrupt
      0.45 ±  2%      -0.1        0.38        perf-profile.children.cycles-pp.switch_fpu_return
      0.37 ±  2%      -0.1        0.30 ±  3%  perf-profile.children.cycles-pp.__hrtimer_run_queues
      0.36 ±  3%      -0.1        0.29 ±  2%  perf-profile.children.cycles-pp.tick_nohz_handler
      0.33 ±  3%      -0.1        0.27 ±  2%  perf-profile.children.cycles-pp.update_process_times
      0.12 ±  5%      -0.1        0.06        perf-profile.children.cycles-pp.available_idle_cpu
      0.14 ±  6%      -0.1        0.09 ±  4%  perf-profile.children.cycles-pp.__flush_smp_call_function_queue
      0.30 ±  2%      -0.1        0.24 ±  2%  perf-profile.children.cycles-pp.__scm_recv_common
      0.46 ±  7%      -0.1        0.41        perf-profile.children.cycles-pp.set_next_entity
      0.32 ±  3%      -0.0        0.27 ±  2%  perf-profile.children.cycles-pp._raw_spin_unlock_irqrestore
      0.29 ±  5%      -0.0        0.24        perf-profile.children.cycles-pp.wakeup_preempt
      0.25            -0.0        0.20        perf-profile.children.cycles-pp.kmalloc_size_roundup
      0.26 ±  3%      -0.0        0.22        perf-profile.children.cycles-pp.prepare_task_switch
      0.29 ±  3%      -0.0        0.24 ±  3%  perf-profile.children.cycles-pp.update_cfs_group
      0.26 ±  3%      -0.0        0.22        perf-profile.children.cycles-pp.rcu_all_qs
      0.32 ±  6%      -0.0        0.28        perf-profile.children.cycles-pp.__rseq_handle_notify_resume
      0.75            -0.0        0.71        perf-profile.children.cycles-pp.unix_write_space
      0.19 ±  4%      -0.0        0.15 ±  2%  perf-profile.children.cycles-pp.finish_task_switch
      0.22 ±  6%      -0.0        0.18 ±  2%  perf-profile.children.cycles-pp.sched_tick
      0.31 ±  4%      -0.0        0.26        perf-profile.children.cycles-pp.restore_fpregs_from_fpstate
      0.24            -0.0        0.20        perf-profile.children.cycles-pp.security_file_permission
      0.16 ±  4%      -0.0        0.12 ±  3%  perf-profile.children.cycles-pp.unix_maybe_add_creds
      0.30 ±  4%      -0.0        0.26        perf-profile.children.cycles-pp.__update_load_avg_se
      0.18 ±  7%      -0.0        0.14 ±  4%  perf-profile.children.cycles-pp.task_tick_fair
      0.25 ±  5%      -0.0        0.21 ±  2%  perf-profile.children.cycles-pp.pick_eevdf
      0.16 ±  6%      -0.0        0.13        perf-profile.children.cycles-pp.asm_sysvec_reschedule_ipi
      0.21 ±  3%      -0.0        0.17 ±  2%  perf-profile.children.cycles-pp.check_stack_object
      0.21 ±  2%      -0.0        0.18 ±  2%  perf-profile.children.cycles-pp.update_rq_clock_task
      0.18 ±  3%      -0.0        0.15 ±  3%  perf-profile.children.cycles-pp.unix_scm_to_skb
      0.23 ±  7%      -0.0        0.19 ±  2%  perf-profile.children.cycles-pp.__update_load_avg_cfs_rq
      0.19 ±  6%      -0.0        0.16 ±  2%  perf-profile.children.cycles-pp.do_perf_trace_sched_wakeup_template
      0.16 ±  3%      -0.0        0.13 ±  3%  perf-profile.children.cycles-pp.is_vmalloc_addr
      0.14 ±  3%      -0.0        0.11 ±  4%  perf-profile.children.cycles-pp.security_socket_sendmsg
      0.18 ±  2%      -0.0        0.15        perf-profile.children.cycles-pp.put_pid
      0.16 ±  3%      -0.0        0.13        perf-profile.children.cycles-pp.put_prev_entity
      0.24 ±  2%      -0.0        0.20 ±  2%  perf-profile.children.cycles-pp.wake_affine
      0.15 ±  2%      -0.0        0.12        perf-profile.children.cycles-pp.manage_oob
      0.22 ±  5%      -0.0        0.19 ±  2%  perf-profile.children.cycles-pp.rseq_ip_fixup
      0.32 ±  2%      -0.0        0.30        perf-profile.children.cycles-pp.reweight_entity
      0.16 ±  2%      -0.0        0.13 ±  5%  perf-profile.children.cycles-pp.security_socket_recvmsg
      0.13 ±  2%      -0.0        0.11 ±  3%  perf-profile.children.cycles-pp.security_socket_getpeersec_dgram
      0.09 ±  7%      -0.0        0.06 ±  7%  perf-profile.children.cycles-pp.cpuacct_charge
      0.30 ±  4%      -0.0        0.28        perf-profile.children.cycles-pp.__enqueue_entity
      0.16 ±  3%      -0.0        0.13 ±  2%  perf-profile.children.cycles-pp.update_curr_se
      0.11 ±  3%      -0.0        0.09        perf-profile.children.cycles-pp.wait_for_unix_gc
      0.10            -0.0        0.08        perf-profile.children.cycles-pp.skb_put
      0.12 ±  7%      -0.0        0.10 ±  3%  perf-profile.children.cycles-pp.os_xsave
      0.10 ±  3%      -0.0        0.08        perf-profile.children.cycles-pp.skb_free_head
      0.13 ±  5%      -0.0        0.12 ±  4%  perf-profile.children.cycles-pp.update_entity_lag
      0.15 ±  7%      -0.0        0.13 ±  3%  perf-profile.children.cycles-pp.update_rq_clock
      0.10 ±  8%      -0.0        0.08        perf-profile.children.cycles-pp.___perf_sw_event
      0.12 ±  6%      -0.0        0.10        perf-profile.children.cycles-pp.perf_tp_event
      0.09            -0.0        0.08 ±  6%  perf-profile.children.cycles-pp.__switch_to_asm
      0.08 ±  6%      -0.0        0.06 ±  7%  perf-profile.children.cycles-pp.kfree_skbmem
      0.09 ±  7%      -0.0        0.08        perf-profile.children.cycles-pp.rseq_update_cpu_node_id
      0.07 ±  5%      -0.0        0.06        perf-profile.children.cycles-pp.__x64_sys_write
      0.06 ±  6%      -0.0        0.05        perf-profile.children.cycles-pp.finish_wait
      0.07            -0.0        0.06        perf-profile.children.cycles-pp.__x64_sys_read
      0.06            -0.0        0.05        perf-profile.children.cycles-pp.__irq_exit_rcu
      0.10 ± 10%      +0.0        0.12 ±  3%  perf-profile.children.cycles-pp.detach_tasks
      0.24 ± 10%      +0.0        0.27 ±  2%  perf-profile.children.cycles-pp.sched_balance_newidle
      0.24 ±  9%      +0.0        0.27 ±  2%  perf-profile.children.cycles-pp.sched_balance_rq
      0.16 ±  3%      +0.0        0.19        perf-profile.children.cycles-pp.put_cpu_partial
      0.19            +0.0        0.24 ±  2%  perf-profile.children.cycles-pp.css_rstat_updated
      0.00            +0.1        0.05        perf-profile.children.cycles-pp.__refill_stock
      0.00            +0.1        0.05        perf-profile.children.cycles-pp.sysvec_call_function
      0.16 ±  2%      +0.1        0.21 ±  2%  perf-profile.children.cycles-pp.refill_stock
      0.14 ±  2%      +0.1        0.19 ±  3%  perf-profile.children.cycles-pp.try_charge_memcg
      0.34 ±  3%      +0.1        0.40 ±  4%  perf-profile.children.cycles-pp.__mod_memcg_lruvec_state
      0.00            +0.1        0.07 ±  5%  perf-profile.children.cycles-pp.asm_sysvec_call_function
      0.32 ±  5%      +0.1        0.40 ±  5%  perf-profile.children.cycles-pp.__mod_memcg_state
      0.42 ±  2%      +0.1        0.56        perf-profile.children.cycles-pp.obj_cgroup_uncharge_pages
      0.12 ± 11%      +0.1        0.26 ±  4%  perf-profile.children.cycles-pp.get_any_partial
     37.92            +0.6       38.52        perf-profile.children.cycles-pp.vfs_write
     36.83            +0.8       37.63        perf-profile.children.cycles-pp.sock_write_iter
     35.67            +1.0       36.68        perf-profile.children.cycles-pp.unix_stream_sendmsg
     50.55            +1.9       52.47        perf-profile.children.cycles-pp.read
     88.56            +2.4       90.94        perf-profile.children.cycles-pp.entry_SYSCALL_64_after_hwframe
     87.95            +2.5       90.43        perf-profile.children.cycles-pp.do_syscall_64
     42.42            +3.4       45.79        perf-profile.children.cycles-pp.ksys_read
     40.72            +3.7       44.41        perf-profile.children.cycles-pp.vfs_read
     39.55            +3.9       43.45        perf-profile.children.cycles-pp.sock_read_iter
     38.72            +4.0       42.77        perf-profile.children.cycles-pp.sock_recvmsg
     38.16            +4.1       42.29        perf-profile.children.cycles-pp.unix_stream_recvmsg
     37.91            +4.2       42.09        perf-profile.children.cycles-pp.unix_stream_read_generic
     18.34            +4.4       22.74        perf-profile.children.cycles-pp.sock_alloc_send_pskb
     15.61 ±  2%      +4.9       20.54        perf-profile.children.cycles-pp.alloc_skb_with_frags
     15.35 ±  2%      +5.0       20.32        perf-profile.children.cycles-pp.__alloc_skb
      4.43 ± 11%      +6.1       10.58 ±  2%  perf-profile.children.cycles-pp.get_partial_node
      5.34 ±  9%      +6.3       11.65 ±  2%  perf-profile.children.cycles-pp.___slab_alloc
      7.59 ±  2%      +7.6       15.16        perf-profile.children.cycles-pp.kmalloc_reserve
      7.08 ±  2%      +7.7       14.73        perf-profile.children.cycles-pp.__kmalloc_node_track_caller_noprof
      6.27 ± 11%      +9.1       15.34 ±  2%  perf-profile.children.cycles-pp.__put_partials
     12.41           +10.2       22.59        perf-profile.children.cycles-pp.consume_skb
      9.06 ±  3%     +10.7       19.74        perf-profile.children.cycles-pp.skb_release_data
      8.42 ±  3%     +10.7       19.13        perf-profile.children.cycles-pp.kfree
     13.33 ±  8%     +14.3       27.59 ±  2%  perf-profile.children.cycles-pp._raw_spin_lock_irqsave
     11.76 ±  9%     +14.3       26.04 ±  2%  perf-profile.children.cycles-pp.native_queued_spin_lock_slowpath
      3.88 ±  2%      -0.8        3.08        perf-profile.self.cycles-pp.__memcg_slab_free_hook
      3.58 ±  6%      -0.8        2.82 ±  5%  perf-profile.self.cycles-pp.fdget_pos
      3.76            -0.7        3.03        perf-profile.self.cycles-pp.clear_bhb_loop
      3.19 ±  3%      -0.6        2.57        perf-profile.self.cycles-pp._raw_spin_lock
      2.41            -0.6        1.82        perf-profile.self.cycles-pp.__slab_free
      2.71 ±  4%      -0.6        2.12        perf-profile.self.cycles-pp.unix_stream_sendmsg
      2.39 ±  2%      -0.4        1.95        perf-profile.self.cycles-pp.unix_stream_read_generic
      2.96 ±  2%      -0.4        2.53        perf-profile.self.cycles-pp._copy_to_iter
      1.71 ±  3%      -0.4        1.30        perf-profile.self.cycles-pp.skb_set_owner_w
      2.40            -0.4        2.02        perf-profile.self.cycles-pp.__memcg_slab_post_alloc_hook
      2.10 ±  3%      -0.4        1.73        perf-profile.self.cycles-pp.sock_wfree
      2.08            -0.4        1.71        perf-profile.self.cycles-pp.do_syscall_64
      1.92            -0.3        1.58        perf-profile.self.cycles-pp.kmem_cache_free
      1.58 ±  8%      -0.3        1.26        perf-profile.self.cycles-pp.sock_def_readable
      2.60 ±  4%      -0.3        2.28        perf-profile.self.cycles-pp._raw_spin_lock_irqsave
      2.22            -0.3        1.95        perf-profile.self.cycles-pp.mod_objcg_state
      1.43 ±  4%      -0.2        1.19 ±  3%  perf-profile.self.cycles-pp.read
      1.41            -0.2        1.18        perf-profile.self.cycles-pp.write
      1.34            -0.2        1.10        perf-profile.self.cycles-pp.entry_SYSRETQ_unsafe_stack
      1.16            -0.2        0.95        perf-profile.self.cycles-pp.__alloc_skb
      1.24            -0.2        1.03        perf-profile.self.cycles-pp._copy_from_iter
      1.34            -0.2        1.14        perf-profile.self.cycles-pp.__kmalloc_node_track_caller_noprof
      1.07 ±  2%      -0.2        0.88        perf-profile.self.cycles-pp.sock_write_iter
      0.63 ± 12%      -0.2        0.46 ±  3%  perf-profile.self.cycles-pp.__switch_to
      0.94 ±  2%      -0.2        0.78        perf-profile.self.cycles-pp.its_return_thunk
      0.94 ±  2%      -0.2        0.77        perf-profile.self.cycles-pp.kmem_cache_alloc_node_noprof
      0.85            -0.2        0.69        perf-profile.self.cycles-pp.fput
      0.84            -0.2        0.69        perf-profile.self.cycles-pp.sock_read_iter
      0.87 ±  2%      -0.1        0.72 ±  3%  perf-profile.self.cycles-pp.vfs_read
      0.83            -0.1        0.70        perf-profile.self.cycles-pp.entry_SYSCALL_64
      0.75 ±  3%      -0.1        0.61        perf-profile.self.cycles-pp.vfs_write
      0.72 ±  2%      -0.1        0.61 ±  2%  perf-profile.self.cycles-pp.__check_heap_object
      0.57 ±  2%      -0.1        0.47        perf-profile.self.cycles-pp.entry_SYSCALL_64_after_hwframe
      0.59            -0.1        0.49        perf-profile.self.cycles-pp.__check_object_size
      0.56            -0.1        0.46        perf-profile.self.cycles-pp.__build_skb_around
      0.61 ±  2%      -0.1        0.50        perf-profile.self.cycles-pp.__skb_datagram_iter
      2.12 ±  2%      -0.1        2.02        perf-profile.self.cycles-pp.check_heap_object
      0.84            -0.1        0.74        perf-profile.self.cycles-pp.refill_obj_stock
      0.54 ±  3%      -0.1        0.45 ±  2%  perf-profile.self.cycles-pp.__virt_addr_valid
      0.42            -0.1        0.34        perf-profile.self.cycles-pp.mutex_unlock
      0.55 ±  3%      -0.1        0.46        perf-profile.self.cycles-pp.syscall_return_via_sysret
      0.45            -0.1        0.37        perf-profile.self.cycles-pp.mutex_lock
      0.47            -0.1        0.38        perf-profile.self.cycles-pp.kfree
      0.40 ±  3%      -0.1        0.32        perf-profile.self.cycles-pp.__schedule
      0.46            -0.1        0.38        perf-profile.self.cycles-pp.unix_write_space
      0.96            -0.1        0.89        perf-profile.self.cycles-pp.obj_cgroup_charge
      0.41            -0.1        0.34 ±  2%  perf-profile.self.cycles-pp.sock_alloc_send_pskb
      0.36 ±  2%      -0.1        0.30        perf-profile.self.cycles-pp.rw_verify_area
      0.38            -0.1        0.32        perf-profile.self.cycles-pp.x64_sys_call
      0.36 ±  2%      -0.1        0.30        perf-profile.self.cycles-pp.__cond_resched
      0.33 ±  2%      -0.1        0.27        perf-profile.self.cycles-pp.ksys_read
      0.33            -0.1        0.27        perf-profile.self.cycles-pp.ksys_write
      0.37 ±  2%      -0.1        0.31        perf-profile.self.cycles-pp.sock_recvmsg
      0.36 ±  2%      -0.1        0.31        perf-profile.self.cycles-pp.update_load_avg
      0.33 ±  2%      -0.1        0.27        perf-profile.self.cycles-pp.skb_copy_datagram_from_iter
      0.28 ±  2%      -0.1        0.23        perf-profile.self.cycles-pp.alloc_skb_with_frags
      0.11 ±  7%      -0.1        0.06        perf-profile.self.cycles-pp.available_idle_cpu
      0.26            -0.0        0.21        perf-profile.self.cycles-pp.entry_SYSCALL_64_safe_stack
      0.27            -0.0        0.22 ±  3%  perf-profile.self.cycles-pp.unix_stream_recvmsg
      0.28 ±  3%      -0.0        0.24        perf-profile.self.cycles-pp.update_cfs_group
      0.28 ±  2%      -0.0        0.24 ±  2%  perf-profile.self.cycles-pp.kmalloc_reserve
      0.30 ±  4%      -0.0        0.26        perf-profile.self.cycles-pp.restore_fpregs_from_fpstate
      0.27 ±  3%      -0.0        0.23        perf-profile.self.cycles-pp._raw_spin_unlock_irqrestore
      0.28 ±  6%      -0.0        0.24        perf-profile.self.cycles-pp.update_curr
      0.24            -0.0        0.20 ±  2%  perf-profile.self.cycles-pp.__scm_recv_common
      0.20 ±  2%      -0.0        0.16 ±  3%  perf-profile.self.cycles-pp.kmalloc_size_roundup
      0.20            -0.0        0.16 ±  3%  perf-profile.self.cycles-pp.security_file_permission
      0.28 ±  5%      -0.0        0.24 ±  2%  perf-profile.self.cycles-pp.__update_load_avg_se
      0.19 ±  2%      -0.0        0.16 ±  2%  perf-profile.self.cycles-pp.unix_destruct_scm
      0.12 ±  4%      -0.0        0.09        perf-profile.self.cycles-pp.unix_maybe_add_creds
      0.22 ±  7%      -0.0        0.18        perf-profile.self.cycles-pp.__update_load_avg_cfs_rq
      0.19 ±  2%      -0.0        0.16        perf-profile.self.cycles-pp.update_rq_clock_task
      0.18 ±  2%      -0.0        0.14 ±  3%  perf-profile.self.cycles-pp.prepare_task_switch
      0.20 ±  2%      -0.0        0.16 ±  3%  perf-profile.self.cycles-pp.rcu_all_qs
      0.14 ±  4%      -0.0        0.11        perf-profile.self.cycles-pp.skb_queue_tail
      0.17 ±  2%      -0.0        0.14 ±  3%  perf-profile.self.cycles-pp.enqueue_task_fair
      0.17 ±  3%      -0.0        0.14        perf-profile.self.cycles-pp.scm_recv_unix
      0.16 ±  3%      -0.0        0.13        perf-profile.self.cycles-pp.unix_scm_to_skb
      0.20 ±  2%      -0.0        0.17        perf-profile.self.cycles-pp.pick_eevdf
      0.13 ±  2%      -0.0        0.10 ±  3%  perf-profile.self.cycles-pp.manage_oob
      0.12 ±  3%      -0.0        0.09 ±  4%  perf-profile.self.cycles-pp.simple_copy_to_iter
      0.14 ±  2%      -0.0        0.11 ±  3%  perf-profile.self.cycles-pp.switch_fpu_return
      0.17 ±  2%      -0.0        0.14        perf-profile.self.cycles-pp.try_to_wake_up
      0.16 ±  2%      -0.0        0.14 ±  2%  perf-profile.self.cycles-pp.check_stack_object
      0.15            -0.0        0.12 ±  4%  perf-profile.self.cycles-pp.skb_unlink
      0.13 ±  2%      -0.0        0.10 ±  4%  perf-profile.self.cycles-pp.__wake_up_common
      0.11 ±  4%      -0.0        0.09        perf-profile.self.cycles-pp.finish_task_switch
      0.12 ±  3%      -0.0        0.10        perf-profile.self.cycles-pp.put_pid
      0.13 ±  2%      -0.0        0.11        perf-profile.self.cycles-pp.consume_skb
      0.13 ±  2%      -0.0        0.11        perf-profile.self.cycles-pp.pick_next_task_fair
      0.14 ±  2%      -0.0        0.12 ±  4%  perf-profile.self.cycles-pp.skb_copy_datagram_iter
      0.30 ±  2%      -0.0        0.28        perf-profile.self.cycles-pp.__enqueue_entity
      0.12 ±  3%      -0.0        0.10 ±  3%  perf-profile.self.cycles-pp.is_vmalloc_addr
      0.11 ±  3%      -0.0        0.09        perf-profile.self.cycles-pp.security_socket_getpeersec_dgram
      0.12 ±  3%      -0.0        0.10        perf-profile.self.cycles-pp.pick_task_fair
      0.10            -0.0        0.08        perf-profile.self.cycles-pp.security_socket_sendmsg
      0.10            -0.0        0.08        perf-profile.self.cycles-pp.select_task_rq
      0.08 ±  5%      -0.0        0.06 ±  7%  perf-profile.self.cycles-pp.cpuacct_charge
      0.13 ±  4%      -0.0        0.11        perf-profile.self.cycles-pp.dequeue_entity
      0.13            -0.0        0.11 ±  5%  perf-profile.self.cycles-pp.security_socket_recvmsg
      0.11            -0.0        0.09        perf-profile.self.cycles-pp.skb_release_head_state
      0.11            -0.0        0.09 ±  4%  perf-profile.self.cycles-pp.enqueue_entity
      0.12 ±  5%      -0.0        0.10        perf-profile.self.cycles-pp.os_xsave
      0.14 ±  3%      -0.0        0.12        perf-profile.self.cycles-pp.update_curr_se
      0.13 ±  5%      -0.0        0.11        perf-profile.self.cycles-pp.exit_to_user_mode_loop
      0.14 ±  4%      -0.0        0.12 ±  3%  perf-profile.self.cycles-pp.task_h_load
      0.12 ±  6%      -0.0        0.11 ±  3%  perf-profile.self.cycles-pp.dequeue_entities
      0.09            -0.0        0.07 ±  6%  perf-profile.self.cycles-pp.wait_for_unix_gc
      0.21 ±  6%      -0.0        0.19 ±  2%  perf-profile.self.cycles-pp.__dequeue_entity
      0.10 ±  5%      -0.0        0.08        perf-profile.self.cycles-pp.__get_user_8
      0.11 ±  6%      -0.0        0.09 ±  5%  perf-profile.self.cycles-pp.prepare_to_wait
      0.08            -0.0        0.06 ±  7%  perf-profile.self.cycles-pp.skb_free_head
      0.08            -0.0        0.06 ±  7%  perf-profile.self.cycles-pp.unix_stream_read_actor
      0.09 ±  4%      -0.0        0.07 ±  6%  perf-profile.self.cycles-pp.__switch_to_asm
      0.12 ±  6%      -0.0        0.11        perf-profile.self.cycles-pp.avg_vruntime
      0.09 ±  4%      -0.0        0.08        perf-profile.self.cycles-pp.place_entity
      0.07 ±  5%      -0.0        0.06        perf-profile.self.cycles-pp.select_task_rq_fair
      0.06 ±  6%      -0.0        0.05        perf-profile.self.cycles-pp.___perf_sw_event
      0.08            -0.0        0.07 ±  5%  perf-profile.self.cycles-pp.skb_put
      0.07            -0.0        0.06        perf-profile.self.cycles-pp.propagate_entity_load_avg
      0.07            -0.0        0.06        perf-profile.self.cycles-pp.wakeup_preempt
      0.06            -0.0        0.05        perf-profile.self.cycles-pp.kfree_skbmem
      0.06            -0.0        0.05        perf-profile.self.cycles-pp.select_idle_sibling
      0.12 ±  3%      +0.0        0.16 ±  4%  perf-profile.self.cycles-pp.obj_cgroup_uncharge_pages
      0.15 ±  3%      +0.0        0.19        perf-profile.self.cycles-pp.put_cpu_partial
      0.10 ±  3%      +0.0        0.14 ±  2%  perf-profile.self.cycles-pp.refill_stock
      0.17            +0.0        0.21        perf-profile.self.cycles-pp.css_rstat_updated
      0.10 ±  4%      +0.0        0.15 ±  3%  perf-profile.self.cycles-pp.try_charge_memcg
      0.27 ±  4%      +0.0        0.31 ±  5%  perf-profile.self.cycles-pp.__mod_memcg_lruvec_state
      0.25 ±  3%      +0.1        0.32        perf-profile.self.cycles-pp.__put_partials
      0.46 ±  3%      +0.1        0.60        perf-profile.self.cycles-pp.get_partial_node
      0.88            +0.2        1.03        perf-profile.self.cycles-pp.___slab_alloc
     11.74 ±  9%     +14.3       26.02 ±  2%  perf-profile.self.cycles-pp.native_queued_spin_lock_slowpath


***************************************************************************************************
lkp-srf-2sp3: 192 threads 2 sockets Intel(R) Xeon(R) 6740E  CPU @ 2.4GHz (Sierra Forest) with 256G memory
=========================================================================================
cluster/compiler/cpufreq_governor/ip/kconfig/nr_threads/rootfs/runtime/tbox_group/test/testcase:
  cs-localhost/gcc-12/performance/ipv4/x86_64-rhel-9.4/50%/debian-12-x86_64-20240206.cgz/300s/lkp-srf-2sp3/SCTP_STREAM/netperf

commit: 
  90b83efa67 ("Merge tag 'bpf-next-6.16' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next")
  2adc2445a5 ("xsk: Fix out of order segment free in __xsk_generic_xmit()")

90b83efa6701656e 2adc2445a5ae93efed1e2e6646a 
---------------- --------------------------- 
         %stddev     %change         %stddev
             \          |                \  
     97891           -14.8%      83440        uptime.idle
 5.813e+10           -24.7%  4.376e+10        cpuidle..time
   1432696         +8071.0%  1.171e+08        cpuidle..usage
      2.67 ±129%  +13268.8%     356.50 ±106%  perf-c2c.DRAM.local
     36.50 ± 97%  +1.7e+05%      62210 ±106%  perf-c2c.HITM.local
     57.83 ± 96%  +1.1e+05%      62785 ±106%  perf-c2c.HITM.total
      7646 ± 24%   +3575.6%     281040 ±196%  numa-meminfo.node0.Shmem
    352954 ± 57%    +397.3%    1755395 ± 35%  numa-meminfo.node1.Active
    352954 ± 57%    +397.3%    1755395 ± 35%  numa-meminfo.node1.Active(anon)
     24856 ±  7%   +5388.7%    1364277 ± 33%  numa-meminfo.node1.Shmem
    900437 ± 18%  +33130.0%  2.992e+08        numa-numastat.node0.local_node
    980894 ± 15%  +30412.3%  2.993e+08        numa-numastat.node0.numa_hit
    843029 ± 20%  +33579.9%  2.839e+08        numa-numastat.node1.local_node
    960593 ± 15%  +29466.0%   2.84e+08        numa-numastat.node1.numa_hit
     99.95           -26.6%      73.35        vmstat.cpu.id
      1.43 ±  4%   +3253.2%      47.88 ±  2%  vmstat.procs.r
      3269        +21229.7%     697353        vmstat.system.cs
      5726 ±  2%   +7837.1%     454486        vmstat.system.in
     99.91           -26.7       73.24        mpstat.cpu.all.idle%
      0.01 ±  2%      +0.3        0.29        mpstat.cpu.all.irq%
      0.03            +6.7        6.71        mpstat.cpu.all.soft%
      0.03 ±  2%     +19.7       19.68        mpstat.cpu.all.sys%
      0.03            +0.1        0.08 ±  3%  mpstat.cpu.all.usr%
      1.00        +15883.3%     159.83 ± 57%  mpstat.max_utilization.seconds
      2.31 ±  3%   +1565.7%      38.48 ±  7%  mpstat.max_utilization_pct
    827685          +197.1%    2459378 ±  3%  meminfo.Active
    827685          +197.1%    2459378 ±  3%  meminfo.Active(anon)
   3564506           +45.3%    5177743        meminfo.Cached
   1002604          +162.8%    2634788 ±  3%  meminfo.Committed_AS
     73396           +27.4%      93496 ±  3%  meminfo.Mapped
   6584486           +30.6%    8597070        meminfo.Memused
     32406         +4978.1%    1645637 ±  5%  meminfo.Shmem
   7674969           +22.1%    9367878        meminfo.max_used_kB
   1475286 ± 37%  +10036.1%  1.495e+08        numa-vmstat.node0.nr_unaccepted
      1910 ± 24%   +3574.4%      70214 ±196%  numa-vmstat.node0.nr_writeback_temp
    901028 ± 18%  +33108.2%  2.992e+08        numa-vmstat.node0.numa_interleave
     88219 ± 57%    +397.4%     438783 ± 35%  numa-vmstat.node1.nr_inactive_anon
   1466007 ± 37%   +9598.9%  1.422e+08        numa-vmstat.node1.nr_unaccepted
      6201 ±  7%   +5398.9%     341002 ± 33%  numa-vmstat.node1.nr_writeback_temp
     88219 ± 57%    +397.4%     438783 ± 35%  numa-vmstat.node1.nr_zone_active_anon
    843731 ± 20%  +33552.0%  2.839e+08        numa-vmstat.node1.numa_interleave
      4.10        +93440.1%       3835        netperf.ThroughputBoth_Mbps
    393.60        +93440.1%     368173        netperf.ThroughputBoth_total_Mbps
      4.10        +93440.1%       3835        netperf.Throughput_Mbps
    393.60        +93440.1%     368173        netperf.Throughput_total_Mbps
     48.00 ±  9%  +1.5e+05%      71216        netperf.time.involuntary_context_switches
     36976          +109.6%      77489        netperf.time.minor_page_faults
      2.00        +89408.3%       1790        netperf.time.percent_of_cpu_this_job_got
      2.65 ±  5%    +2e+05%       5407        netperf.time.system_time
     70144        +75110.0%   52755811        netperf.time.voluntary_context_switches
     69331        +76173.9%   52881525        netperf.workload
     18597           +20.9%      22487        proc-vmstat.nr_anon_pages
    206982          +196.9%     614442 ±  3%  proc-vmstat.nr_inactive_anon
    891142           +45.2%    1294018        proc-vmstat.nr_mapped
    130794            +2.6%     134152        proc-vmstat.nr_slab_reclaimable
   2940843         +9808.2%  2.914e+08        proc-vmstat.nr_unaccepted
     36043            +2.6%      36994        proc-vmstat.nr_unevictable
      8116         +4963.7%     410990 ±  5%  proc-vmstat.nr_writeback_temp
    206982          +196.9%     614442 ±  3%  proc-vmstat.nr_zone_active_anon
      2758 ± 12%    +466.4%      15626 ± 11%  proc-vmstat.numa_hint_faults
      3103 ±183%   +1123.1%      37957 ± 15%  proc-vmstat.numa_hint_faults_local
      5180 ± 88%    +991.6%      56556 ± 10%  proc-vmstat.numa_huge_pte_updates
   1746716        +33285.4%  5.831e+08        proc-vmstat.numa_interleave
      3103 ±183%   +1123.1%      37957 ± 15%  proc-vmstat.numa_pages_migrated
  22862693        +81149.0%  1.858e+10        proc-vmstat.pgalloc_dma32
    962895           +11.6%    1074237        proc-vmstat.pglazyfree
     42493           +28.3%      54507        proc-vmstat.pgrefill
  22791848        +81398.7%  1.858e+10        proc-vmstat.pgskip_device
    199829            +2.3%     204523        proc-vmstat.workingset_nodereclaim
      8.77 ±  2%     -96.3%       0.32        perf-stat.i.MPKI
  77235971         +7812.2%  6.111e+09        perf-stat.i.branch-instructions
      1.93            -1.4        0.55        perf-stat.i.branch-miss-rate%
   3411141          +880.6%   33448138        perf-stat.i.branch-misses
     22.30 ±  2%     -21.6        0.71        perf-stat.i.cache-miss-rate%
   1665598 ±  2%    +511.2%   10179755        perf-stat.i.cache-misses
   7250815        +31692.2%  2.305e+09        perf-stat.i.cache-references
      3208        +21832.1%     703722        perf-stat.i.context-switches
      3.61           +37.5%       4.96        perf-stat.i.cpi
 7.967e+08        +19662.7%  1.574e+11        perf-stat.i.cpu-cycles
    268.09         +1572.7%       4484        perf-stat.i.cpu-migrations
    470.08         +3392.1%      16415        perf-stat.i.cycles-between-cache-misses
 3.771e+08         +8315.9%  3.173e+10        perf-stat.i.instructions
      0.31           -33.5%       0.21        perf-stat.i.ipc
      2789           +12.7%       3145        perf-stat.i.minor-faults
      2789           +12.7%       3145        perf-stat.i.page-faults
      4.42 ±  2%     -92.7%       0.32        perf-stat.overall.MPKI
      4.42            -3.9        0.55        perf-stat.overall.branch-miss-rate%
     22.97 ±  2%     -22.5        0.44        perf-stat.overall.cache-miss-rate%
      2.11          +134.8%       4.96        perf-stat.overall.cpi
    478.64 ±  2%   +3130.5%      15462        perf-stat.overall.cycles-between-cache-misses
      0.47           -57.4%       0.20        perf-stat.overall.ipc
   1638835           -88.9%     181352        perf-stat.overall.path-length
  76999412         +7810.5%  6.091e+09        perf-stat.ps.branch-instructions
   3401355          +880.2%   33339495        perf-stat.ps.branch-misses
   1659790 ±  2%    +511.5%   10149201        perf-stat.ps.cache-misses
   7226565        +31693.0%  2.298e+09        perf-stat.ps.cache-references
      3197        +21832.0%     701377        perf-stat.ps.context-switches
 7.941e+08        +19659.7%  1.569e+11        perf-stat.ps.cpu-cycles
    267.21         +1572.9%       4470        perf-stat.ps.cpu-migrations
 3.759e+08         +8313.8%  3.163e+10        perf-stat.ps.instructions
      2780           +12.7%       3133        perf-stat.ps.minor-faults
      2780           +12.7%       3133        perf-stat.ps.page-faults
 1.136e+11         +8340.5%   9.59e+12        perf-stat.total.instructions
      3740 ± 12%  +29693.1%    1114329 ± 10%  sched_debug.cfs_rq:/.avg_vruntime.avg
     56542 ± 15%   +2339.5%    1379378 ±  8%  sched_debug.cfs_rq:/.avg_vruntime.max
    369.53 ± 16%  +1.6e+05%     579756 ± 20%  sched_debug.cfs_rq:/.avg_vruntime.min
      6898 ± 20%   +1820.7%     132511 ± 26%  sched_debug.cfs_rq:/.avg_vruntime.stddev
      0.02 ± 12%   +1118.1%       0.22 ±  6%  sched_debug.cfs_rq:/.h_nr_queued.avg
      0.13 ±  6%    +212.0%       0.40        sched_debug.cfs_rq:/.h_nr_queued.stddev
      0.02 ± 12%   +1116.5%       0.22 ±  5%  sched_debug.cfs_rq:/.h_nr_runnable.avg
      0.13 ±  6%    +211.4%       0.40        sched_debug.cfs_rq:/.h_nr_runnable.stddev
     14.16 ±132%  +48472.6%       6875 ± 21%  sched_debug.cfs_rq:/.left_deadline.avg
      2717 ±132%  +27785.8%     757891 ± 19%  sched_debug.cfs_rq:/.left_deadline.max
    195.63 ±132%  +35354.2%      69359 ± 15%  sched_debug.cfs_rq:/.left_deadline.stddev
     14.11 ±133%  +48627.1%       6874 ± 21%  sched_debug.cfs_rq:/.left_vruntime.avg
      2708 ±133%  +27874.6%     757818 ± 19%  sched_debug.cfs_rq:/.left_vruntime.max
    194.99 ±133%  +35466.9%      69352 ± 15%  sched_debug.cfs_rq:/.left_vruntime.stddev
    618037 ± 36%     -66.7%     205834 ± 48%  sched_debug.cfs_rq:/.load.max
     51379 ± 30%     -57.6%      21767 ± 30%  sched_debug.cfs_rq:/.load.stddev
    687.50 ±  9%     -64.9%     241.44 ± 24%  sched_debug.cfs_rq:/.load_avg.max
     83.99 ±  6%     -49.9%      42.10 ± 29%  sched_debug.cfs_rq:/.load_avg.stddev
      3740 ± 12%  +29693.1%    1114329 ± 10%  sched_debug.cfs_rq:/.min_vruntime.avg
     56542 ± 15%   +2339.5%    1379378 ±  8%  sched_debug.cfs_rq:/.min_vruntime.max
    369.53 ± 16%  +1.6e+05%     579756 ± 20%  sched_debug.cfs_rq:/.min_vruntime.min
      6899 ± 20%   +1820.7%     132511 ± 26%  sched_debug.cfs_rq:/.min_vruntime.stddev
      0.02 ± 13%   +1109.9%       0.22 ±  5%  sched_debug.cfs_rq:/.nr_queued.avg
      0.13 ±  7%    +210.9%       0.40 ±  2%  sched_debug.cfs_rq:/.nr_queued.stddev
     14.12 ±133%  +48603.5%       6874 ± 21%  sched_debug.cfs_rq:/.right_vruntime.avg
      2710 ±133%  +27861.0%     757818 ± 19%  sched_debug.cfs_rq:/.right_vruntime.max
    195.09 ±133%  +35449.7%      69352 ± 15%  sched_debug.cfs_rq:/.right_vruntime.stddev
     35.41 ±  6%    +493.0%     209.98 ±  5%  sched_debug.cfs_rq:/.runnable_avg.avg
    685.83 ±  4%     +35.7%     930.48 ±  5%  sched_debug.cfs_rq:/.runnable_avg.max
     83.58 ±  4%    +188.8%     241.42 ±  2%  sched_debug.cfs_rq:/.runnable_avg.stddev
     35.30 ±  6%    +494.6%     209.91 ±  5%  sched_debug.cfs_rq:/.util_avg.avg
    680.17 ±  5%     +36.8%     930.40 ±  5%  sched_debug.cfs_rq:/.util_avg.max
     83.16 ±  4%    +190.3%     241.37 ±  2%  sched_debug.cfs_rq:/.util_avg.stddev
      3.01 ± 38%   +3061.8%      95.09 ±  7%  sched_debug.cfs_rq:/.util_est.avg
    249.27 ± 31%    +131.8%     577.82 ±  2%  sched_debug.cfs_rq:/.util_est.max
     23.40 ± 29%    +671.1%     180.43 ±  2%  sched_debug.cfs_rq:/.util_est.stddev
    968260           -56.6%     420088 ±  9%  sched_debug.cpu.avg_idle.avg
    134682 ± 51%     -64.3%      48084 ±  4%  sched_debug.cpu.avg_idle.min
     94988 ±  6%    +233.8%     317085 ±  8%  sched_debug.cpu.avg_idle.stddev
     10.48 ±  2%     +16.1%      12.18 ±  2%  sched_debug.cpu.clock.stddev
    526.86          +230.8%       1742 ± 13%  sched_debug.cpu.clock_task.stddev
     67.14 ± 12%   +1549.7%       1107 ±  5%  sched_debug.cpu.curr->pid.avg
    652.41 ±  3%    +205.6%       1993        sched_debug.cpu.curr->pid.stddev
      0.00 ±  4%     +15.1%       0.00 ±  5%  sched_debug.cpu.next_balance.stddev
      0.01 ± 20%   +1565.3%       0.22 ±  5%  sched_debug.cpu.nr_running.avg
      0.10 ±  9%    +286.8%       0.40        sched_debug.cpu.nr_running.stddev
      3400 ±  5%  +15458.0%     529068 ±  8%  sched_debug.cpu.nr_switches.avg
     54421 ± 22%   +1031.5%     615757 ±  7%  sched_debug.cpu.nr_switches.max
      1015 ±  7%  +26519.5%     270329 ± 12%  sched_debug.cpu.nr_switches.min
      5199 ± 22%    +721.5%      42712 ±  6%  sched_debug.cpu.nr_switches.stddev
      0.01 ± 17%     +60.3%       0.02 ±  5%  perf-sched.sch_delay.avg.ms.__cond_resched.__wait_for_common.affine_move_task.__set_cpus_allowed_ptr.__sched_setaffinity
      0.02 ± 17%     -39.1%       0.01 ± 17%  perf-sched.sch_delay.avg.ms.__x64_sys_pause.do_syscall_64.entry_SYSCALL_64_after_hwframe.[unknown]
      0.01 ±  5%     +31.4%       0.01 ±  6%  perf-sched.sch_delay.avg.ms.anon_pipe_read.fifo_pipe_read.vfs_read.ksys_read
      0.04 ± 75%     -66.8%       0.01 ± 13%  perf-sched.sch_delay.avg.ms.do_nanosleep.hrtimer_nanosleep.common_nsleep.__x64_sys_clock_nanosleep
      0.01 ±  4%     +30.9%       0.01 ±  4%  perf-sched.sch_delay.avg.ms.do_wait.kernel_wait4.do_syscall_64.entry_SYSCALL_64_after_hwframe
      0.01 ± 88%    +375.6%       0.03 ± 54%  perf-sched.sch_delay.avg.ms.irqentry_exit_to_user_mode.asm_sysvec_apic_timer_interrupt.[unknown].[unknown]
      0.02 ± 13%     -47.0%       0.01 ± 20%  perf-sched.sch_delay.avg.ms.schedule_hrtimeout_range_clock.ep_poll.do_epoll_wait.__x64_sys_epoll_wait
      0.01 ±  7%     +38.7%       0.01 ±  9%  perf-sched.sch_delay.avg.ms.schedule_timeout.__wait_for_common.wait_for_completion_state.kernel_clone
      0.02 ±  4%     -28.6%       0.01 ±  6%  perf-sched.sch_delay.avg.ms.schedule_timeout.kcompactd.kthread.ret_from_fork
      0.21 ± 62%     -96.6%       0.01 ±  5%  perf-sched.sch_delay.avg.ms.schedule_timeout.sctp_skb_recv_datagram.sctp_recvmsg.inet_recvmsg
      0.32 ±138%     -97.7%       0.01 ± 10%  perf-sched.sch_delay.avg.ms.schedule_timeout.sctp_wait_for_sndbuf.sctp_sendmsg_to_asoc.sctp_sendmsg
      0.01 ± 26%    +334.9%       0.03 ± 11%  perf-sched.sch_delay.avg.ms.smpboot_thread_fn.kthread.ret_from_fork.ret_from_fork_asm
      1.05 ±217%     -98.1%       0.02 ±  6%  perf-sched.sch_delay.avg.ms.worker_thread.kthread.ret_from_fork.ret_from_fork_asm
      0.03 ± 20%     -54.7%       0.01 ± 17%  perf-sched.sch_delay.max.ms.__x64_sys_pause.do_syscall_64.entry_SYSCALL_64_after_hwframe.[unknown]
      0.12 ±147%     -85.3%       0.02 ± 11%  perf-sched.sch_delay.max.ms.do_nanosleep.hrtimer_nanosleep.common_nsleep.__x64_sys_clock_nanosleep
      0.02 ±  9%    +235.9%       0.07 ±112%  perf-sched.sch_delay.max.ms.do_wait.kernel_wait4.do_syscall_64.entry_SYSCALL_64_after_hwframe
      0.03 ± 41%  +2.7e+05%      68.69 ±222%  perf-sched.sch_delay.max.ms.exit_to_user_mode_loop.do_syscall_64.entry_SYSCALL_64_after_hwframe.[unknown]
      0.01 ± 86%   +1267.4%       0.10 ± 65%  perf-sched.sch_delay.max.ms.irqentry_exit_to_user_mode.asm_sysvec_apic_timer_interrupt.[unknown].[unknown]
      0.04 ±  6%     -50.8%       0.02 ± 22%  perf-sched.sch_delay.max.ms.schedule_hrtimeout_range_clock.ep_poll.do_epoll_wait.__x64_sys_epoll_wait
      0.01 ± 10%    +139.2%       0.03 ± 61%  perf-sched.sch_delay.max.ms.schedule_timeout.__wait_for_common.wait_for_completion_state.kernel_clone
      0.03 ± 22%     -48.7%       0.02 ±  3%  perf-sched.sch_delay.max.ms.schedule_timeout.kcompactd.kthread.ret_from_fork
    207.81          +150.3%     520.18 ± 46%  perf-sched.sch_delay.max.ms.schedule_timeout.sctp_skb_recv_datagram.sctp_recvmsg.inet_recvmsg
      1.79 ±118%   +1020.4%      20.01 ± 62%  perf-sched.sch_delay.max.ms.smpboot_thread_fn.kthread.ret_from_fork.ret_from_fork_asm
      0.16 ±103%     -95.3%       0.01 ±  6%  perf-sched.total_sch_delay.average.ms
    252.56           -99.4%       1.56 ±  2%  perf-sched.total_wait_and_delay.average.ms
     10166        +15987.4%    1635446        perf-sched.total_wait_and_delay.count.ms
      4984           -15.6%       4204 ±  7%  perf-sched.total_wait_and_delay.max.ms
    252.40           -99.4%       1.55 ±  2%  perf-sched.total_wait_time.average.ms
      4984           -15.6%       4204 ±  7%  perf-sched.total_wait_time.max.ms
      7.83           -55.1%       3.52        perf-sched.wait_and_delay.avg.ms.__cond_resched.__wait_for_common.affine_move_task.__set_cpus_allowed_ptr.__sched_setaffinity
    184.60 ±  4%     +14.9%     212.10        perf-sched.wait_and_delay.avg.ms.anon_pipe_read.fifo_pipe_read.vfs_read.ksys_read
      0.47          -100.0%       0.00        perf-sched.wait_and_delay.avg.ms.do_wait.kernel_wait4.do_syscall_64.entry_SYSCALL_64_after_hwframe
      0.60 ±  4%    -100.0%       0.00        perf-sched.wait_and_delay.avg.ms.schedule_timeout.__wait_for_common.wait_for_completion_state.kernel_clone
    199.50           -99.8%       0.43 ±  3%  perf-sched.wait_and_delay.avg.ms.schedule_timeout.sctp_skb_recv_datagram.sctp_recvmsg.inet_recvmsg
    381.71           -99.9%       0.43 ±  3%  perf-sched.wait_and_delay.avg.ms.schedule_timeout.sctp_wait_for_sndbuf.sctp_sendmsg_to_asoc.sctp_sendmsg
    604.00           -77.6%     135.41 ±  4%  perf-sched.wait_and_delay.avg.ms.smpboot_thread_fn.kthread.ret_from_fork.ret_from_fork_asm
    797.02 ±  3%     -18.0%     653.44        perf-sched.wait_and_delay.avg.ms.worker_thread.kthread.ret_from_fork.ret_from_fork_asm
    217.83 ±  4%     -13.4%     188.67        perf-sched.wait_and_delay.count.anon_pipe_read.fifo_pipe_read.vfs_read.ksys_read
    126.33          -100.0%       0.00        perf-sched.wait_and_delay.count.do_wait.kernel_wait4.do_syscall_64.entry_SYSCALL_64_after_hwframe
     88.17          -100.0%       0.00        perf-sched.wait_and_delay.count.schedule_timeout.__wait_for_common.wait_for_completion_state.kernel_clone
      2310        +34913.6%     808931        perf-sched.wait_and_delay.count.schedule_timeout.sctp_skb_recv_datagram.sctp_recvmsg.inet_recvmsg
      1157        +69710.6%     807941        perf-sched.wait_and_delay.count.schedule_timeout.sctp_wait_for_sndbuf.sctp_sendmsg_to_asoc.sctp_sendmsg
      1600          +346.1%       7140 ±  5%  perf-sched.wait_and_delay.count.smpboot_thread_fn.kthread.ret_from_fork.ret_from_fork_asm
    723.83 ±  2%     +60.2%       1159        perf-sched.wait_and_delay.count.worker_thread.kthread.ret_from_fork.ret_from_fork_asm
      4984           -79.9%       1000        perf-sched.wait_and_delay.max.ms.__cond_resched.__wait_for_common.affine_move_task.__set_cpus_allowed_ptr.__sched_setaffinity
     16.98 ±  2%    -100.0%       0.00        perf-sched.wait_and_delay.max.ms.do_wait.kernel_wait4.do_syscall_64.entry_SYSCALL_64_after_hwframe
      2.23 ±  6%    -100.0%       0.00        perf-sched.wait_and_delay.max.ms.schedule_timeout.__wait_for_common.wait_for_completion_state.kernel_clone
    209.37          +491.8%       1239 ± 31%  perf-sched.wait_and_delay.max.ms.schedule_timeout.sctp_skb_recv_datagram.sctp_recvmsg.inet_recvmsg
    417.22          +155.0%       1063        perf-sched.wait_and_delay.max.ms.schedule_timeout.sctp_wait_for_sndbuf.sctp_sendmsg_to_asoc.sctp_sendmsg
      4122 ± 10%     -35.0%       2679 ± 17%  perf-sched.wait_and_delay.max.ms.worker_thread.kthread.ret_from_fork.ret_from_fork_asm
      7.81           -55.3%       3.49        perf-sched.wait_time.avg.ms.__cond_resched.__wait_for_common.affine_move_task.__set_cpus_allowed_ptr.__sched_setaffinity
    184.59 ±  4%     +14.9%     212.09        perf-sched.wait_time.avg.ms.anon_pipe_read.fifo_pipe_read.vfs_read.ksys_read
      0.46            +9.9%       0.51        perf-sched.wait_time.avg.ms.do_wait.kernel_wait4.do_syscall_64.entry_SYSCALL_64_after_hwframe
    375.09 ± 24%     -99.7%       1.19 ± 48%  perf-sched.wait_time.avg.ms.exit_to_user_mode_loop.do_syscall_64.entry_SYSCALL_64_after_hwframe.[unknown]
      4.04           +10.5%       4.47 ±  3%  perf-sched.wait_time.avg.ms.rcu_gp_kthread.kthread.ret_from_fork.ret_from_fork_asm
      0.60 ±  4%     +11.2%       0.66 ±  3%  perf-sched.wait_time.avg.ms.schedule_timeout.__wait_for_common.wait_for_completion_state.kernel_clone
    199.29           -99.8%       0.43 ±  3%  perf-sched.wait_time.avg.ms.schedule_timeout.sctp_skb_recv_datagram.sctp_recvmsg.inet_recvmsg
    381.39           -99.9%       0.42 ±  3%  perf-sched.wait_time.avg.ms.schedule_timeout.sctp_wait_for_sndbuf.sctp_sendmsg_to_asoc.sctp_sendmsg
    604.00           -77.6%     135.38 ±  4%  perf-sched.wait_time.avg.ms.smpboot_thread_fn.kthread.ret_from_fork.ret_from_fork_asm
    795.97 ±  3%     -17.9%     653.42        perf-sched.wait_time.avg.ms.worker_thread.kthread.ret_from_fork.ret_from_fork_asm
      4984           -79.9%       1000        perf-sched.wait_time.max.ms.__cond_resched.__wait_for_common.affine_move_task.__set_cpus_allowed_ptr.__sched_setaffinity
      2.23 ±  6%     +21.9%       2.71 ±  6%  perf-sched.wait_time.max.ms.schedule_timeout.__wait_for_common.wait_for_completion_state.kernel_clone
    209.31          +408.2%       1063        perf-sched.wait_time.max.ms.schedule_timeout.sctp_skb_recv_datagram.sctp_recvmsg.inet_recvmsg
    417.20          +155.0%       1063        perf-sched.wait_time.max.ms.schedule_timeout.sctp_wait_for_sndbuf.sctp_sendmsg_to_asoc.sctp_sendmsg
      4122 ± 10%     -35.0%       2679 ± 17%  perf-sched.wait_time.max.ms.worker_thread.kthread.ret_from_fork.ret_from_fork_asm





Disclaimer:
Results have been estimated based on internal Intel analysis and are provided
for informational purposes only. Any difference in system hardware or software
design or configuration may affect actual performance.


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Re: [PATCH bpf v2] xsk: Fix out of order segment free in __xsk_generic_xmit()

[kernel test robot]

:::::: 
:::::: Manual check reason: "__compiletime_assert_NNN"
:::::: 

BCC: lkp@intel.com
CC: llvm@lists.linux.dev
CC: oe-kbuild-all@lists.linux.dev
In-Reply-To: <20250530103456.53564-1-e.kubanski@partner.samsung.com>
References: <20250530103456.53564-1-e.kubanski@partner.samsung.com>
TO: "e.kubanski" <e.kubanski@partner.samsung.com>
TO: netdev@vger.kernel.org
TO: linux-kernel@vger.kernel.org
CC: bjorn@kernel.org
CC: magnus.karlsson@intel.com
CC: maciej.fijalkowski@intel.com
CC: jonathan.lemon@gmail.com
CC: "e.kubanski" <e.kubanski@partner.samsung.com>

Hi e.kubanski,

kernel test robot noticed the following build errors:

[auto build test ERROR on bpf/master]

url:    https://github.com/intel-lab-lkp/linux/commits/e-kubanski/xsk-Fix-out-of-order-segment-free-in-__xsk_generic_xmit/20250530-183723
base:   https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf.git master
patch link:    https://lore.kernel.org/r/20250530103456.53564-1-e.kubanski%40partner.samsung.com
patch subject: [PATCH bpf v2] xsk: Fix out of order segment free in __xsk_generic_xmit()
:::::: branch date: 24 hours ago
:::::: commit date: 24 hours ago
config: arm64-allmodconfig (https://download.01.org/0day-ci/archive/20250531/202505311701.ysDKIyGZ-lkp@intel.com/config)
compiler: clang version 19.1.7 (https://github.com/llvm/llvm-project cd708029e0b2869e80abe31ddb175f7c35361f90)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250531/202505311701.ysDKIyGZ-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/r/202505311701.ysDKIyGZ-lkp@intel.com/

All errors (new ones prefixed by >>):

>> drivers/net/ethernet/meta/fbnic/fbnic_txrx.c:2184:6: error: call to '__compiletime_assert_1551' declared with 'error' attribute: FIELD_PREP: value too large for the field
    2184 |             FIELD_PREP(FBNIC_QUEUE_RDE_CTL0_MIN_TROOM_MASK, FBNIC_RX_TROOM);
         |             ^
   include/linux/bitfield.h:115:3: note: expanded from macro 'FIELD_PREP'
     115 |                 __BF_FIELD_CHECK(_mask, 0ULL, _val, "FIELD_PREP: ");    \
         |                 ^
   include/linux/bitfield.h:68:3: note: expanded from macro '__BF_FIELD_CHECK'
      68 |                 BUILD_BUG_ON_MSG(__builtin_constant_p(_val) ?           \
         |                 ^
   include/linux/build_bug.h:39:37: note: expanded from macro 'BUILD_BUG_ON_MSG'
      39 | #define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg)
         |                                     ^
   note: (skipping 1 expansions in backtrace; use -fmacro-backtrace-limit=0 to see all)
   include/linux/compiler_types.h:550:2: note: expanded from macro '_compiletime_assert'
     550 |         __compiletime_assert(condition, msg, prefix, suffix)
         |         ^
   include/linux/compiler_types.h:543:4: note: expanded from macro '__compiletime_assert'
     543 |                         prefix ## suffix();                             \
         |                         ^
   <scratch space>:23:1: note: expanded from here
      23 | __compiletime_assert_1551
         | ^
   1 error generated.


vim +2184 drivers/net/ethernet/meta/fbnic/fbnic_txrx.c

0cb4c0a13723ef Alexander Duyck 2024-07-12  2173  
0cb4c0a13723ef Alexander Duyck 2024-07-12  2174  static void fbnic_config_drop_mode_rcq(struct fbnic_napi_vector *nv,
0cb4c0a13723ef Alexander Duyck 2024-07-12  2175  				       struct fbnic_ring *rcq)
0cb4c0a13723ef Alexander Duyck 2024-07-12  2176  {
0cb4c0a13723ef Alexander Duyck 2024-07-12  2177  	u32 drop_mode, rcq_ctl;
0cb4c0a13723ef Alexander Duyck 2024-07-12  2178  
0cb4c0a13723ef Alexander Duyck 2024-07-12  2179  	drop_mode = FBNIC_QUEUE_RDE_CTL0_DROP_IMMEDIATE;
0cb4c0a13723ef Alexander Duyck 2024-07-12  2180  
0cb4c0a13723ef Alexander Duyck 2024-07-12  2181  	/* Specify packet layout */
0cb4c0a13723ef Alexander Duyck 2024-07-12  2182  	rcq_ctl = FIELD_PREP(FBNIC_QUEUE_RDE_CTL0_DROP_MODE_MASK, drop_mode) |
0cb4c0a13723ef Alexander Duyck 2024-07-12  2183  	    FIELD_PREP(FBNIC_QUEUE_RDE_CTL0_MIN_HROOM_MASK, FBNIC_RX_HROOM) |
0cb4c0a13723ef Alexander Duyck 2024-07-12 @2184  	    FIELD_PREP(FBNIC_QUEUE_RDE_CTL0_MIN_TROOM_MASK, FBNIC_RX_TROOM);
0cb4c0a13723ef Alexander Duyck 2024-07-12  2185  
0cb4c0a13723ef Alexander Duyck 2024-07-12  2186  	fbnic_ring_wr32(rcq, FBNIC_QUEUE_RDE_CTL0, rcq_ctl);
0cb4c0a13723ef Alexander Duyck 2024-07-12  2187  }
0cb4c0a13723ef Alexander Duyck 2024-07-12  2188  

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