* [PATCH] RDMA/rxe: Fix null-ptr-deref in kernel_sock_shutdown().
@ 2026-04-24 1:37 Kuniyuki Iwashima
2026-04-24 3:10 ` Zhu Yanjun
0 siblings, 1 reply; 3+ messages in thread
From: Kuniyuki Iwashima @ 2026-04-24 1:37 UTC (permalink / raw)
To: Zhu Yanjun, Jason Gunthorpe, Leon Romanovsky
Cc: Kuniyuki Iwashima, Kuniyuki Iwashima, linux-rdma,
syzbot+d8f76778263ab65c2b21
syzbot reported null-ptr-deref in kernel_sock_shutdown(). [0]
The problem is rxe_net_del() can be called for the same
device concurrently.
Multiple threads might call udp_tunnel_sock_release()
for the same socket.
Let's add a per-netns mutex to synchronise rxe_net_del().
[0]:
Oops: general protection fault, probably for non-canonical address 0xdffffc000000000d: 0000 [#1] SMP KASAN NOPTI
KASAN: null-ptr-deref in range [0x0000000000000068-0x000000000000006f]
CPU: 3 UID: 0 PID: 12652 Comm: syz.7.1709 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
RIP: 0010:kernel_sock_shutdown+0x47/0x70 net/socket.c:3785
Code: fc ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 75 33 48 b8 00 00 00 00 00 fc ff df 4c 8b 63 20 49 8d 7c 24 68 48 89 fa 48 c1 ea 03 <80> 3c 02 00 75 1a 49 8b 44 24 68 89 ee 48 89 df 5b 5d 41 5c e9 46
RSP: 0018:ffffc9000566f180 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: ffff888058587240 RCX: 0000000000000000
RDX: 000000000000000d RSI: ffffffff895ced12 RDI: 0000000000000068
RBP: 0000000000000002 R08: 0000000000000001 R09: ffffed1006d98945
R10: ffff888036cc4a2b R11: 0000003683c25c00 R12: 0000000000000000
R13: ffff88805c998000 R14: 0000000000000002 R15: 0000000000000018
FS: 00007f1306d976c0(0000) GS:ffff8880d65db000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f1306d97d58 CR3: 00000000404f1000 CR4: 0000000000352ef0
DR0: ffffffffffffffff DR1: 00000000000001f8 DR2: 0000000000000002
DR3: ffffffffefffff15 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
udp_tunnel_sock_release+0x68/0x80 net/ipv4/udp_tunnel_core.c:202
rxe_release_udp_tunnel drivers/infiniband/sw/rxe/rxe_net.c:294 [inline]
rxe_sock_put+0xae/0x130 drivers/infiniband/sw/rxe/rxe_net.c:639
rxe_net_del+0x83/0x120 drivers/infiniband/sw/rxe/rxe_net.c:660
rxe_dellink+0x15/0x20 drivers/infiniband/sw/rxe/rxe.c:254
nldev_dellink+0x289/0x3c0 drivers/infiniband/core/nldev.c:1849
rdma_nl_rcv_msg+0x392/0x6f0 drivers/infiniband/core/netlink.c:195
rdma_nl_rcv_skb.constprop.0.isra.0+0x2cb/0x410 drivers/infiniband/core/netlink.c:239
netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
netlink_unicast+0x585/0x850 net/netlink/af_netlink.c:1344
netlink_sendmsg+0x8b0/0xda0 net/netlink/af_netlink.c:1894
sock_sendmsg_nosec net/socket.c:787 [inline]
__sock_sendmsg net/socket.c:802 [inline]
____sys_sendmsg+0x9e1/0xb70 net/socket.c:2698
___sys_sendmsg+0x190/0x1e0 net/socket.c:2752
__sys_sendmsg+0x170/0x220 net/socket.c:2784
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x10b/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f1305f9c819
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f1306d97028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f1306216090 RCX: 00007f1305f9c819
RDX: 0000000000000000 RSI: 00002000000002c0 RDI: 0000000000000003
RBP: 00007f1306032c91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f1306216128 R14: 00007f1306216090 R15: 00007ffd8ecad288
</TASK>
Modules linked in:
Fixes: f1327abd6abe ("RDMA/rxe: Support RDMA link creation and destruction per net namespace")
Reported-by: syzbot+d8f76778263ab65c2b21@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/all/69ea344f.a00a0220.17a17.0040.GAE@google.com/
Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
---
drivers/infiniband/sw/rxe/rxe_net.c | 2 ++
drivers/infiniband/sw/rxe/rxe_ns.c | 18 ++++++++++++++++++
drivers/infiniband/sw/rxe/rxe_ns.h | 2 ++
3 files changed, 22 insertions(+)
diff --git a/drivers/infiniband/sw/rxe/rxe_net.c b/drivers/infiniband/sw/rxe/rxe_net.c
index 50a2cb5405e2..1b3615c9262a 100644
--- a/drivers/infiniband/sw/rxe/rxe_net.c
+++ b/drivers/infiniband/sw/rxe/rxe_net.c
@@ -655,6 +655,7 @@ void rxe_net_del(struct ib_device *dev)
net = dev_net(ndev);
+ rxe_ns_pernet_sk_lock(net);
sk = rxe_ns_pernet_sk4(net);
if (sk)
rxe_sock_put(sk, rxe_ns_pernet_set_sk4, net);
@@ -662,6 +663,7 @@ void rxe_net_del(struct ib_device *dev)
sk = rxe_ns_pernet_sk6(net);
if (sk)
rxe_sock_put(sk, rxe_ns_pernet_set_sk6, net);
+ rxe_ns_pernet_sk_unlock(net);
dev_put(ndev);
}
diff --git a/drivers/infiniband/sw/rxe/rxe_ns.c b/drivers/infiniband/sw/rxe/rxe_ns.c
index 8b9d734229b2..375c7d79d9d3 100644
--- a/drivers/infiniband/sw/rxe/rxe_ns.c
+++ b/drivers/infiniband/sw/rxe/rxe_ns.c
@@ -16,6 +16,7 @@
struct rxe_ns_sock {
struct sock __rcu *rxe_sk4;
struct sock __rcu *rxe_sk6;
+ struct mutex rxe_sk_lock;
};
/*
@@ -28,9 +29,12 @@ static unsigned int rxe_pernet_id;
*/
static int rxe_ns_init(struct net *net)
{
+ struct rxe_ns_sock *ns_sk = net_generic(net, rxe_pernet_id);
+
/* defer socket create in the namespace to the first
* device create.
*/
+ mutex_init(&ns_sk->rxe_sk_lock);
return 0;
}
@@ -71,6 +75,20 @@ static struct pernet_operations rxe_net_ops = {
.size = sizeof(struct rxe_ns_sock),
};
+void rxe_ns_pernet_sk_lock(struct net *net)
+{
+ struct rxe_ns_sock *ns_sk = net_generic(net, rxe_pernet_id);
+
+ mutex_lock(&ns_sk->rxe_sk_lock);
+}
+
+void rxe_ns_pernet_sk_unlock(struct net *net)
+{
+ struct rxe_ns_sock *ns_sk = net_generic(net, rxe_pernet_id);
+
+ mutex_unlock(&ns_sk->rxe_sk_lock);
+}
+
struct sock *rxe_ns_pernet_sk4(struct net *net)
{
struct rxe_ns_sock *ns_sk = net_generic(net, rxe_pernet_id);
diff --git a/drivers/infiniband/sw/rxe/rxe_ns.h b/drivers/infiniband/sw/rxe/rxe_ns.h
index 4da2709e6b71..c5262843bb63 100644
--- a/drivers/infiniband/sw/rxe/rxe_ns.h
+++ b/drivers/infiniband/sw/rxe/rxe_ns.h
@@ -3,6 +3,8 @@
#ifndef RXE_NS_H
#define RXE_NS_H
+void rxe_ns_pernet_sk_lock(struct net *net);
+void rxe_ns_pernet_sk_unlock(struct net *net);
struct sock *rxe_ns_pernet_sk4(struct net *net);
void rxe_ns_pernet_set_sk4(struct net *net, struct sock *sk);
--
2.54.0.rc2.544.gc7ae2d5bb8-goog
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] RDMA/rxe: Fix null-ptr-deref in kernel_sock_shutdown().
2026-04-24 1:37 [PATCH] RDMA/rxe: Fix null-ptr-deref in kernel_sock_shutdown() Kuniyuki Iwashima
@ 2026-04-24 3:10 ` Zhu Yanjun
2026-04-25 0:06 ` Kuniyuki Iwashima
0 siblings, 1 reply; 3+ messages in thread
From: Zhu Yanjun @ 2026-04-24 3:10 UTC (permalink / raw)
To: Kuniyuki Iwashima, Zhu Yanjun, Jason Gunthorpe, Leon Romanovsky,
yanjun.zhu@linux.dev
Cc: Kuniyuki Iwashima, linux-rdma, syzbot+d8f76778263ab65c2b21
在 2026/4/23 18:37, Kuniyuki Iwashima 写道:
> syzbot reported null-ptr-deref in kernel_sock_shutdown(). [0]
>
> The problem is rxe_net_del() can be called for the same
> device concurrently.
>
> Multiple threads might call udp_tunnel_sock_release()
> for the same socket.
>
> Let's add a per-netns mutex to synchronise rxe_net_del().
>
> [0]:
> Oops: general protection fault, probably for non-canonical address 0xdffffc000000000d: 0000 [#1] SMP KASAN NOPTI
> KASAN: null-ptr-deref in range [0x0000000000000068-0x000000000000006f]
> CPU: 3 UID: 0 PID: 12652 Comm: syz.7.1709 Tainted: G L syzkaller #0 PREEMPT(full)
> Tainted: [L]=SOFTLOCKUP
> Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
> RIP: 0010:kernel_sock_shutdown+0x47/0x70 net/socket.c:3785
> Code: fc ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 75 33 48 b8 00 00 00 00 00 fc ff df 4c 8b 63 20 49 8d 7c 24 68 48 89 fa 48 c1 ea 03 <80> 3c 02 00 75 1a 49 8b 44 24 68 89 ee 48 89 df 5b 5d 41 5c e9 46
> RSP: 0018:ffffc9000566f180 EFLAGS: 00010202
> RAX: dffffc0000000000 RBX: ffff888058587240 RCX: 0000000000000000
> RDX: 000000000000000d RSI: ffffffff895ced12 RDI: 0000000000000068
> RBP: 0000000000000002 R08: 0000000000000001 R09: ffffed1006d98945
> R10: ffff888036cc4a2b R11: 0000003683c25c00 R12: 0000000000000000
> R13: ffff88805c998000 R14: 0000000000000002 R15: 0000000000000018
> FS: 00007f1306d976c0(0000) GS:ffff8880d65db000(0000) knlGS:0000000000000000
> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 00007f1306d97d58 CR3: 00000000404f1000 CR4: 0000000000352ef0
> DR0: ffffffffffffffff DR1: 00000000000001f8 DR2: 0000000000000002
> DR3: ffffffffefffff15 DR6: 00000000ffff0ff0 DR7: 0000000000000400
> Call Trace:
> <TASK>
> udp_tunnel_sock_release+0x68/0x80 net/ipv4/udp_tunnel_core.c:202
> rxe_release_udp_tunnel drivers/infiniband/sw/rxe/rxe_net.c:294 [inline]
> rxe_sock_put+0xae/0x130 drivers/infiniband/sw/rxe/rxe_net.c:639
> rxe_net_del+0x83/0x120 drivers/infiniband/sw/rxe/rxe_net.c:660
> rxe_dellink+0x15/0x20 drivers/infiniband/sw/rxe/rxe.c:254
> nldev_dellink+0x289/0x3c0 drivers/infiniband/core/nldev.c:1849
> rdma_nl_rcv_msg+0x392/0x6f0 drivers/infiniband/core/netlink.c:195
> rdma_nl_rcv_skb.constprop.0.isra.0+0x2cb/0x410 drivers/infiniband/core/netlink.c:239
> netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
> netlink_unicast+0x585/0x850 net/netlink/af_netlink.c:1344
> netlink_sendmsg+0x8b0/0xda0 net/netlink/af_netlink.c:1894
> sock_sendmsg_nosec net/socket.c:787 [inline]
> __sock_sendmsg net/socket.c:802 [inline]
> ____sys_sendmsg+0x9e1/0xb70 net/socket.c:2698
> ___sys_sendmsg+0x190/0x1e0 net/socket.c:2752
> __sys_sendmsg+0x170/0x220 net/socket.c:2784
> do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
> do_syscall_64+0x10b/0xf80 arch/x86/entry/syscall_64.c:94
> entry_SYSCALL_64_after_hwframe+0x77/0x7f
> RIP: 0033:0x7f1305f9c819
> Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
> RSP: 002b:00007f1306d97028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
> RAX: ffffffffffffffda RBX: 00007f1306216090 RCX: 00007f1305f9c819
> RDX: 0000000000000000 RSI: 00002000000002c0 RDI: 0000000000000003
> RBP: 00007f1306032c91 R08: 0000000000000000 R09: 0000000000000000
> R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
> R13: 00007f1306216128 R14: 00007f1306216090 R15: 00007ffd8ecad288
> </TASK>
> Modules linked in:
>
> Fixes: f1327abd6abe ("RDMA/rxe: Support RDMA link creation and destruction per net namespace")
> Reported-by: syzbot+d8f76778263ab65c2b21@syzkaller.appspotmail.com
> Closes: https://lore.kernel.org/all/69ea344f.a00a0220.17a17.0040.GAE@google.com/
> Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
> ---
> drivers/infiniband/sw/rxe/rxe_net.c | 2 ++
> drivers/infiniband/sw/rxe/rxe_ns.c | 18 ++++++++++++++++++
> drivers/infiniband/sw/rxe/rxe_ns.h | 2 ++
> 3 files changed, 22 insertions(+)
>
> diff --git a/drivers/infiniband/sw/rxe/rxe_net.c b/drivers/infiniband/sw/rxe/rxe_net.c
> index 50a2cb5405e2..1b3615c9262a 100644
> --- a/drivers/infiniband/sw/rxe/rxe_net.c
> +++ b/drivers/infiniband/sw/rxe/rxe_net.c
> @@ -655,6 +655,7 @@ void rxe_net_del(struct ib_device *dev)
>
> net = dev_net(ndev);
>
> + rxe_ns_pernet_sk_lock(net);
> sk = rxe_ns_pernet_sk4(net);
> if (sk)
> rxe_sock_put(sk, rxe_ns_pernet_set_sk4, net);
> @@ -662,6 +663,7 @@ void rxe_net_del(struct ib_device *dev)
> sk = rxe_ns_pernet_sk6(net);
> if (sk)
> rxe_sock_put(sk, rxe_ns_pernet_set_sk6, net);
> + rxe_ns_pernet_sk_unlock(net);
If one thread is calling rxe_net_del (destroying the socket) while
another thread simultaneously
calls rxe_newlink to create the socket, I am not sure if a race
condition will occur or not.
If yes, I think all locations that modify these pointers should hold the
mutex.
>
> dev_put(ndev);
> }
> diff --git a/drivers/infiniband/sw/rxe/rxe_ns.c b/drivers/infiniband/sw/rxe/rxe_ns.c
> index 8b9d734229b2..375c7d79d9d3 100644
> --- a/drivers/infiniband/sw/rxe/rxe_ns.c
> +++ b/drivers/infiniband/sw/rxe/rxe_ns.c
> @@ -16,6 +16,7 @@
> struct rxe_ns_sock {
> struct sock __rcu *rxe_sk4;
> struct sock __rcu *rxe_sk6;
> + struct mutex rxe_sk_lock;
> };
>
> /*
> @@ -28,9 +29,12 @@ static unsigned int rxe_pernet_id;
> */
> static int rxe_ns_init(struct net *net)
> {
> + struct rxe_ns_sock *ns_sk = net_generic(net, rxe_pernet_id);
> +
> /* defer socket create in the namespace to the first
> * device create.
> */
> + mutex_init(&ns_sk->rxe_sk_lock);
The lock is initialized in rxe_ns_init, but this lock is not handled in
rxe_ns_exit
(or the corresponding cleanup function).
Although a mutex typically does not require special operations upon
destruction,
the presence of pending lock contention could potentially cause the
namespace destruction process to hang.
So in rxe_ns_exit or other cleanup functions, add
"mutex_destroy(&ns_sk->rxe_sk_lock);"
This seems more professional.
>
> return 0;
> }
> @@ -71,6 +75,20 @@ static struct pernet_operations rxe_net_ops = {
> .size = sizeof(struct rxe_ns_sock),
> };
>
> +void rxe_ns_pernet_sk_lock(struct net *net)
> +{
> + struct rxe_ns_sock *ns_sk = net_generic(net, rxe_pernet_id);
> +
> + mutex_lock(&ns_sk->rxe_sk_lock);
> +}
> +
> +void rxe_ns_pernet_sk_unlock(struct net *net)
> +{
> + struct rxe_ns_sock *ns_sk = net_generic(net, rxe_pernet_id);
> +
> + mutex_unlock(&ns_sk->rxe_sk_lock);
> +}
> +
Introducing a mutex lock will serialize all RXE device deletion operations
within the same network namespace (netns). Although deletion is not a
fast path operation, it may increase control-plane latency in environments
with a large number of virtual adapters. It is necessary to verify
whether a more
lightweight solution (such as an xchg atomic exchange operation) exists to
handle the extraction and nullification of the socket pointers.
Although rxe is a simulation driver, it does not focus on the
performance. But a lighter lock
might as well benefit the whole system
Thanks a lot.
Zhu Yanjun
> struct sock *rxe_ns_pernet_sk4(struct net *net)
> {
> struct rxe_ns_sock *ns_sk = net_generic(net, rxe_pernet_id);
> diff --git a/drivers/infiniband/sw/rxe/rxe_ns.h b/drivers/infiniband/sw/rxe/rxe_ns.h
> index 4da2709e6b71..c5262843bb63 100644
> --- a/drivers/infiniband/sw/rxe/rxe_ns.h
> +++ b/drivers/infiniband/sw/rxe/rxe_ns.h
> @@ -3,6 +3,8 @@
> #ifndef RXE_NS_H
> #define RXE_NS_H
>
> +void rxe_ns_pernet_sk_lock(struct net *net);
> +void rxe_ns_pernet_sk_unlock(struct net *net);
> struct sock *rxe_ns_pernet_sk4(struct net *net);
> void rxe_ns_pernet_set_sk4(struct net *net, struct sock *sk);
>
--
Best Regards,
Yanjun.Zhu
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] RDMA/rxe: Fix null-ptr-deref in kernel_sock_shutdown().
2026-04-24 3:10 ` Zhu Yanjun
@ 2026-04-25 0:06 ` Kuniyuki Iwashima
0 siblings, 0 replies; 3+ messages in thread
From: Kuniyuki Iwashima @ 2026-04-25 0:06 UTC (permalink / raw)
To: Zhu Yanjun
Cc: Zhu Yanjun, Jason Gunthorpe, Leon Romanovsky, Kuniyuki Iwashima,
linux-rdma, syzbot+d8f76778263ab65c2b21
On Thu, Apr 23, 2026 at 8:10 PM Zhu Yanjun <yanjun.zhu@linux.dev> wrote:
>
>
> 在 2026/4/23 18:37, Kuniyuki Iwashima 写道:
> > syzbot reported null-ptr-deref in kernel_sock_shutdown(). [0]
> >
> > The problem is rxe_net_del() can be called for the same
> > device concurrently.
> >
> > Multiple threads might call udp_tunnel_sock_release()
> > for the same socket.
> >
> > Let's add a per-netns mutex to synchronise rxe_net_del().
> >
> > [0]:
> > Oops: general protection fault, probably for non-canonical address 0xdffffc000000000d: 0000 [#1] SMP KASAN NOPTI
> > KASAN: null-ptr-deref in range [0x0000000000000068-0x000000000000006f]
> > CPU: 3 UID: 0 PID: 12652 Comm: syz.7.1709 Tainted: G L syzkaller #0 PREEMPT(full)
> > Tainted: [L]=SOFTLOCKUP
> > Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
> > RIP: 0010:kernel_sock_shutdown+0x47/0x70 net/socket.c:3785
> > Code: fc ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 75 33 48 b8 00 00 00 00 00 fc ff df 4c 8b 63 20 49 8d 7c 24 68 48 89 fa 48 c1 ea 03 <80> 3c 02 00 75 1a 49 8b 44 24 68 89 ee 48 89 df 5b 5d 41 5c e9 46
> > RSP: 0018:ffffc9000566f180 EFLAGS: 00010202
> > RAX: dffffc0000000000 RBX: ffff888058587240 RCX: 0000000000000000
> > RDX: 000000000000000d RSI: ffffffff895ced12 RDI: 0000000000000068
> > RBP: 0000000000000002 R08: 0000000000000001 R09: ffffed1006d98945
> > R10: ffff888036cc4a2b R11: 0000003683c25c00 R12: 0000000000000000
> > R13: ffff88805c998000 R14: 0000000000000002 R15: 0000000000000018
> > FS: 00007f1306d976c0(0000) GS:ffff8880d65db000(0000) knlGS:0000000000000000
> > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> > CR2: 00007f1306d97d58 CR3: 00000000404f1000 CR4: 0000000000352ef0
> > DR0: ffffffffffffffff DR1: 00000000000001f8 DR2: 0000000000000002
> > DR3: ffffffffefffff15 DR6: 00000000ffff0ff0 DR7: 0000000000000400
> > Call Trace:
> > <TASK>
> > udp_tunnel_sock_release+0x68/0x80 net/ipv4/udp_tunnel_core.c:202
> > rxe_release_udp_tunnel drivers/infiniband/sw/rxe/rxe_net.c:294 [inline]
> > rxe_sock_put+0xae/0x130 drivers/infiniband/sw/rxe/rxe_net.c:639
> > rxe_net_del+0x83/0x120 drivers/infiniband/sw/rxe/rxe_net.c:660
> > rxe_dellink+0x15/0x20 drivers/infiniband/sw/rxe/rxe.c:254
> > nldev_dellink+0x289/0x3c0 drivers/infiniband/core/nldev.c:1849
> > rdma_nl_rcv_msg+0x392/0x6f0 drivers/infiniband/core/netlink.c:195
> > rdma_nl_rcv_skb.constprop.0.isra.0+0x2cb/0x410 drivers/infiniband/core/netlink.c:239
> > netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
> > netlink_unicast+0x585/0x850 net/netlink/af_netlink.c:1344
> > netlink_sendmsg+0x8b0/0xda0 net/netlink/af_netlink.c:1894
> > sock_sendmsg_nosec net/socket.c:787 [inline]
> > __sock_sendmsg net/socket.c:802 [inline]
> > ____sys_sendmsg+0x9e1/0xb70 net/socket.c:2698
> > ___sys_sendmsg+0x190/0x1e0 net/socket.c:2752
> > __sys_sendmsg+0x170/0x220 net/socket.c:2784
> > do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
> > do_syscall_64+0x10b/0xf80 arch/x86/entry/syscall_64.c:94
> > entry_SYSCALL_64_after_hwframe+0x77/0x7f
> > RIP: 0033:0x7f1305f9c819
> > Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
> > RSP: 002b:00007f1306d97028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
> > RAX: ffffffffffffffda RBX: 00007f1306216090 RCX: 00007f1305f9c819
> > RDX: 0000000000000000 RSI: 00002000000002c0 RDI: 0000000000000003
> > RBP: 00007f1306032c91 R08: 0000000000000000 R09: 0000000000000000
> > R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
> > R13: 00007f1306216128 R14: 00007f1306216090 R15: 00007ffd8ecad288
> > </TASK>
> > Modules linked in:
> >
> > Fixes: f1327abd6abe ("RDMA/rxe: Support RDMA link creation and destruction per net namespace")
> > Reported-by: syzbot+d8f76778263ab65c2b21@syzkaller.appspotmail.com
> > Closes: https://lore.kernel.org/all/69ea344f.a00a0220.17a17.0040.GAE@google.com/
> > Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
> > ---
> > drivers/infiniband/sw/rxe/rxe_net.c | 2 ++
> > drivers/infiniband/sw/rxe/rxe_ns.c | 18 ++++++++++++++++++
> > drivers/infiniband/sw/rxe/rxe_ns.h | 2 ++
> > 3 files changed, 22 insertions(+)
> >
> > diff --git a/drivers/infiniband/sw/rxe/rxe_net.c b/drivers/infiniband/sw/rxe/rxe_net.c
> > index 50a2cb5405e2..1b3615c9262a 100644
> > --- a/drivers/infiniband/sw/rxe/rxe_net.c
> > +++ b/drivers/infiniband/sw/rxe/rxe_net.c
> > @@ -655,6 +655,7 @@ void rxe_net_del(struct ib_device *dev)
> >
> > net = dev_net(ndev);
> >
> > + rxe_ns_pernet_sk_lock(net);
> > sk = rxe_ns_pernet_sk4(net);
> > if (sk)
> > rxe_sock_put(sk, rxe_ns_pernet_set_sk4, net);
> > @@ -662,6 +663,7 @@ void rxe_net_del(struct ib_device *dev)
> > sk = rxe_ns_pernet_sk6(net);
> > if (sk)
> > rxe_sock_put(sk, rxe_ns_pernet_set_sk6, net);
> > + rxe_ns_pernet_sk_unlock(net);
>
> If one thread is calling rxe_net_del (destroying the socket) while
> another thread simultaneously
>
> calls rxe_newlink to create the socket, I am not sure if a race
> condition will occur or not.
>
> If yes, I think all locations that modify these pointers should hold the
> mutex.
I haven't looked into newlink path as dellink had
__sock_put(), but yeah, it looks very racy.
> >
> > dev_put(ndev);
> > }
> > diff --git a/drivers/infiniband/sw/rxe/rxe_ns.c b/drivers/infiniband/sw/rxe/rxe_ns.c
> > index 8b9d734229b2..375c7d79d9d3 100644
> > --- a/drivers/infiniband/sw/rxe/rxe_ns.c
> > +++ b/drivers/infiniband/sw/rxe/rxe_ns.c
> > @@ -16,6 +16,7 @@
> > struct rxe_ns_sock {
> > struct sock __rcu *rxe_sk4;
> > struct sock __rcu *rxe_sk6;
> > + struct mutex rxe_sk_lock;
> > };
> >
> > /*
> > @@ -28,9 +29,12 @@ static unsigned int rxe_pernet_id;
> > */
> > static int rxe_ns_init(struct net *net)
> > {
> > + struct rxe_ns_sock *ns_sk = net_generic(net, rxe_pernet_id);
> > +
> > /* defer socket create in the namespace to the first
> > * device create.
> > */
> > + mutex_init(&ns_sk->rxe_sk_lock);
>
> The lock is initialized in rxe_ns_init, but this lock is not handled in
> rxe_ns_exit
>
> (or the corresponding cleanup function).
>
> Although a mutex typically does not require special operations upon
> destruction,
>
> the presence of pending lock contention could potentially cause the
> namespace destruction process to hang.
>
> So in rxe_ns_exit or other cleanup functions, add
> "mutex_destroy(&ns_sk->rxe_sk_lock);"
>
> This seems more professional.
>
> >
> > return 0;
> > }
> > @@ -71,6 +75,20 @@ static struct pernet_operations rxe_net_ops = {
> > .size = sizeof(struct rxe_ns_sock),
> > };
> >
> > +void rxe_ns_pernet_sk_lock(struct net *net)
> > +{
> > + struct rxe_ns_sock *ns_sk = net_generic(net, rxe_pernet_id);
> > +
> > + mutex_lock(&ns_sk->rxe_sk_lock);
> > +}
> > +
> > +void rxe_ns_pernet_sk_unlock(struct net *net)
> > +{
> > + struct rxe_ns_sock *ns_sk = net_generic(net, rxe_pernet_id);
> > +
> > + mutex_unlock(&ns_sk->rxe_sk_lock);
> > +}
> > +
>
> Introducing a mutex lock will serialize all RXE device deletion operations
>
> within the same network namespace (netns). Although deletion is not a
>
> fast path operation, it may increase control-plane latency in environments
>
> with a large number of virtual adapters. It is necessary to verify
> whether a more
>
> lightweight solution (such as an xchg atomic exchange operation) exists to
>
> handle the extraction and nullification of the socket pointers.
>
> Although rxe is a simulation driver, it does not focus on the
> performance. But a lighter lock
>
> might as well benefit the whole system
I will move socket creation/destruction to __net_init and
__net_exit instead of adding mutex. Then, sock_hold()
and __sock_put() will be unnecessary too.
I don't find a good reason to defer socket creation to
the first device creation, which needs synchronisation
within the same netns anyway.
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2026-04-25 0:06 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2026-04-24 1:37 [PATCH] RDMA/rxe: Fix null-ptr-deref in kernel_sock_shutdown() Kuniyuki Iwashima
2026-04-24 3:10 ` Zhu Yanjun
2026-04-25 0:06 ` Kuniyuki Iwashima
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox