[PATCH 6.6 68/72] ptr_ring: do not block hard interrupts in ptr_ring_resize_multiple()

Greg Kroah-Hartman
2026-02-04T15:22:47Z

From: Eric Dumazet <edumazet@google.com>

[ Upstream commit a126061c80d5efb4baef4bcf346094139cd81df6 ]

Jakub added a lockdep_assert_no_hardirq() check in __page_pool_put_page()
to increase test coverage.

syzbot found a splat caused by hard irq blocking in
ptr_ring_resize_multiple() [1]

As current users of ptr_ring_resize_multiple() do not require
hard irqs being masked, replace it to only block BH.

Rename helpers to better reflect they are safe against BH only.

- ptr_ring_resize_multiple() to ptr_ring_resize_multiple_bh()
- skb_array_resize_multiple() to skb_array_resize_multiple_bh()

[1]

WARNING: CPU: 1 PID: 9150 at net/core/page_pool.c:709 __page_pool_put_page net/core/page_pool.c:709 [inline]
WARNING: CPU: 1 PID: 9150 at net/core/page_pool.c:709 page_pool_put_unrefed_netmem+0x157/0xa40 net/core/page_pool.c:780
Modules linked in:
CPU: 1 UID: 0 PID: 9150 Comm: syz.1.1052 Not tainted 6.11.0-rc3-syzkaller-00202-gf8669d7b5f5d #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/06/2024
RIP: 0010:__page_pool_put_page net/core/page_pool.c:709 [inline]
RIP: 0010:page_pool_put_unrefed_netmem+0x157/0xa40 net/core/page_pool.c:780
Code: 74 0e e8 7c aa fb f7 eb 43 e8 75 aa fb f7 eb 3c 65 8b 1d 38 a8 6a 76 31 ff 89 de e8 a3 ae fb f7 85 db 74 0b e8 5a aa fb f7 90 <0f> 0b 90 eb 1d 65 8b 1d 15 a8 6a 76 31 ff 89 de e8 84 ae fb f7 85
RSP: 0018:ffffc9000bda6b58 EFLAGS: 00010083
RAX: ffffffff8997e523 RBX: 0000000000000000 RCX: 0000000000040000
RDX: ffffc9000fbd0000 RSI: 0000000000001842 RDI: 0000000000001843
RBP: 0000000000000000 R08: ffffffff8997df2c R09: 1ffffd40003a000d
R10: dffffc0000000000 R11: fffff940003a000e R12: ffffea0001d00040
R13: ffff88802e8a4000 R14: dffffc0000000000 R15: 00000000ffffffff
FS: 00007fb7aaf716c0(0000) GS:ffff8880b9300000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fa15a0d4b72 CR3: 00000000561b0000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
tun_ptr_free drivers/net/tun.c:617 [inline]
__ptr_ring_swap_queue include/linux/ptr_ring.h:571 [inline]
ptr_ring_resize_multiple_noprof include/linux/ptr_ring.h:643 [inline]
tun_queue_resize drivers/net/tun.c:3694 [inline]
tun_device_event+0xaaf/0x1080 drivers/net/tun.c:3714
notifier_call_chain+0x19f/0x3e0 kernel/notifier.c:93
call_netdevice_notifiers_extack net/core/dev.c:2032 [inline]
call_netdevice_notifiers net/core/dev.c:2046 [inline]
dev_change_tx_queue_len+0x158/0x2a0 net/core/dev.c:9024
do_setlink+0xff6/0x41f0 net/core/rtnetlink.c:2923
rtnl_setlink+0x40d/0x5a0 net/core/rtnetlink.c:3201
rtnetlink_rcv_msg+0x73f/0xcf0 net/core/rtnetlink.c:6647
netlink_rcv_skb+0x1e3/0x430 net/netlink/af_netlink.c:2550

Fixes: ff4e538c8c3e ("page_pool: add a lockdep check for recycling in hardirq")
Reported-by: syzbot+f56a5c5eac2b28439810@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/netdev/671e10df.050a0220.2b8c0f.01cf.GAE@google.com/T/
Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Link: https://patch.msgid.link/20241217135121.326370-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
[ 2c321f3f70bc ("mm: change inlined allocation helpers to account at the call site")
is not ported to Linux-6.6.y. So remove the suffix "_noprof". ]
Signed-off-by: Alva Lan <alvalan9@foxmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/net/tap.c | 6 +++---
drivers/net/tun.c | 6 +++---
include/linux/ptr_ring.h | 17 ++++++++---------
include/linux/skb_array.h | 14 ++++++++------
net/sched/sch_generic.c | 4 ++--
5 files changed, 24 insertions(+), 23 deletions(-)

--- a/drivers/net/tap.c
+++ b/drivers/net/tap.c
@@ -1330,9 +1330,9 @@ int tap_queue_resize(struct tap_dev *tap
list_for_each_entry(q, &tap->queue_list, next)
rings[i++] = &q->ring;

- ret = ptr_ring_resize_multiple(rings, n,
- dev->tx_queue_len, GFP_KERNEL,
- __skb_array_destroy_skb);
+ ret = ptr_ring_resize_multiple_bh(rings, n,
+ dev->tx_queue_len, GFP_KERNEL,
+ __skb_array_destroy_skb);

kfree(rings);
return ret;
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -3682,9 +3682,9 @@ static int tun_queue_resize(struct tun_s
list_for_each_entry(tfile, &tun->disabled, next)
rings[i++] = &tfile->tx_ring;

- ret = ptr_ring_resize_multiple(rings, n,
- dev->tx_queue_len, GFP_KERNEL,
- tun_ptr_free);
+ ret = ptr_ring_resize_multiple_bh(rings, n,
+ dev->tx_queue_len, GFP_KERNEL,
+ tun_ptr_free);

kfree(rings);
return ret;
--- a/include/linux/ptr_ring.h
+++ b/include/linux/ptr_ring.h
@@ -613,15 +613,14 @@ static inline int ptr_ring_resize(struct
/*
* Note: producer lock is nested within consumer lock, so if you
* resize you must make sure all uses nest correctly.
- * In particular if you consume ring in interrupt or BH context, you must
- * disable interrupts/BH when doing so.
+ * In particular if you consume ring in BH context, you must
+ * disable BH when doing so.
*/
-static inline int ptr_ring_resize_multiple(struct ptr_ring **rings,
- unsigned int nrings,
- int size,
- gfp_t gfp, void (*destroy)(void *))
+static inline int ptr_ring_resize_multiple_bh(struct ptr_ring **rings,
+ unsigned int nrings,
+ int size, gfp_t gfp,
+ void (*destroy)(void *))
{
- unsigned long flags;
void ***queues;
int i;

@@ -636,12 +635,12 @@ static inline int ptr_ring_resize_multip
}

for (i = 0; i < nrings; ++i) {
- spin_lock_irqsave(&(rings[i])->consumer_lock, flags);
+ spin_lock_bh(&(rings[i])->consumer_lock);
spin_lock(&(rings[i])->producer_lock);
queues[i] = __ptr_ring_swap_queue(rings[i], queues[i],
size, gfp, destroy);
spin_unlock(&(rings[i])->producer_lock);
- spin_unlock_irqrestore(&(rings[i])->consumer_lock, flags);
+ spin_unlock_bh(&(rings[i])->consumer_lock);
}

for (i = 0; i < nrings; ++i)
--- a/include/linux/skb_array.h
+++ b/include/linux/skb_array.h
@@ -198,16 +198,18 @@ static inline int skb_array_resize(struc
return ptr_ring_resize(&a->ring, size, gfp, __skb_array_destroy_skb);
}

-static inline int skb_array_resize_multiple(struct skb_array **rings,
- int nrings, unsigned int size,
- gfp_t gfp)
+static inline int skb_array_resize_multiple_bh(struct skb_array **rings,
+ int nrings,
+ unsigned int size,
+ gfp_t gfp)
{
BUILD_BUG_ON(offsetof(struct skb_array, ring));
- return ptr_ring_resize_multiple((struct ptr_ring **)rings,
- nrings, size, gfp,
- __skb_array_destroy_skb);
+ return ptr_ring_resize_multiple_bh((struct ptr_ring **)rings,
+ nrings, size, gfp,
+ __skb_array_destroy_skb);
}

+
static inline void skb_array_cleanup(struct skb_array *a)
{
ptr_ring_cleanup(&a->ring, __skb_array_destroy_skb);
--- a/net/sched/sch_generic.c
+++ b/net/sched/sch_generic.c
@@ -910,8 +910,8 @@ static int pfifo_fast_change_tx_queue_le
bands[prio] = q;
}

- return skb_array_resize_multiple(bands, PFIFO_FAST_BANDS, new_len,
- GFP_KERNEL);
+ return skb_array_resize_multiple_bh(bands, PFIFO_FAST_BANDS, new_len,
+ GFP_KERNEL);
}

struct Qdisc_ops pfifo_fast_ops __read_mostly = {