This is a note to let you know that I've just added the patch titled net: hsr: remove WARN_ONCE() in send_hsr_supervision_frame() to the 5.10-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: net-hsr-remove-warn_once-in-send_hsr_supervision_frame.patch and it can be found in the queue-5.10 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 37e8c97e539015637cb920d3e6f1e404f707a06e Mon Sep 17 00:00:00 2001 From: Nikita Zhandarovich <n.zhandarovich@xxxxxxxxxx> Date: Wed, 24 Jan 2024 02:21:47 -0800 Subject: net: hsr: remove WARN_ONCE() in send_hsr_supervision_frame() From: Nikita Zhandarovich <n.zhandarovich@xxxxxxxxxx> commit 37e8c97e539015637cb920d3e6f1e404f707a06e upstream. Syzkaller reported [1] hitting a warning after failing to allocate resources for skb in hsr_init_skb(). Since a WARN_ONCE() call will not help much in this case, it might be prudent to switch to netdev_warn_once(). At the very least it will suppress syzkaller reports such as [1]. Just in case, use netdev_warn_once() in send_prp_supervision_frame() for similar reasons. [1] HSR: Could not send supervision frame WARNING: CPU: 1 PID: 85 at net/hsr/hsr_device.c:294 send_hsr_supervision_frame+0x60a/0x810 net/hsr/hsr_device.c:294 RIP: 0010:send_hsr_supervision_frame+0x60a/0x810 net/hsr/hsr_device.c:294 .. Call Trace: <IRQ> hsr_announce+0x114/0x370 net/hsr/hsr_device.c:382 call_timer_fn+0x193/0x590 kernel/time/timer.c:1700 expire_timers kernel/time/timer.c:1751 [inline] __run_timers+0x764/0xb20 kernel/time/timer.c:2022 run_timer_softirq+0x58/0xd0 kernel/time/timer.c:2035 __do_softirq+0x21a/0x8de kernel/softirq.c:553 invoke_softirq kernel/softirq.c:427 [inline] __irq_exit_rcu kernel/softirq.c:632 [inline] irq_exit_rcu+0xb7/0x120 kernel/softirq.c:644 sysvec_apic_timer_interrupt+0x95/0xb0 arch/x86/kernel/apic/apic.c:1076 </IRQ> <TASK> asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:649 .. This issue is also found in older kernels (at least up to 5.10). Cc: stable@xxxxxxxxxxxxxxx Reported-by: syzbot+3ae0a3f42c84074b7c8e@xxxxxxxxxxxxxxxxxxxxxxxxx Fixes: 121c33b07b31 ("net: hsr: introduce common code for skb initialization") Signed-off-by: Nikita Zhandarovich <n.zhandarovich@xxxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- net/hsr/hsr_device.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/net/hsr/hsr_device.c +++ b/net/hsr/hsr_device.c @@ -291,7 +291,7 @@ static void send_hsr_supervision_frame(s skb = hsr_init_skb(master); if (!skb) { - WARN_ONCE(1, "HSR: Could not send supervision frame\n"); + netdev_warn_once(master->dev, "HSR: Could not send supervision frame\n"); return; } @@ -338,7 +338,7 @@ static void send_prp_supervision_frame(s skb = hsr_init_skb(master); if (!skb) { - WARN_ONCE(1, "PRP: Could not send supervision frame\n"); + netdev_warn_once(master->dev, "PRP: Could not send supervision frame\n"); return; } Patches currently in stable-queue which might be from n.zhandarovich@xxxxxxxxxx are queue-5.10/net-hsr-remove-warn_once-in-send_hsr_supervision_frame.patch