syzbot


WARNING in br_nf_local_in (2)

Status: upstream: reported on 2026/01/11 11:35
Subsystems: bridge netfilter
[Documentation on labels]
Reported-by: syzbot+9c5dd93a81a3f39325c2@syzkaller.appspotmail.com
First crash: 2d06h, last: 2d06h
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [bridge?] [netfilter?] WARNING in br_nf_local_in (2) 0 (1) 2026/01/11 11:35
Similar bugs (3)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-5.15 WARNING in br_nf_local_in -1 1 529d 529d 0/3 auto-obsoleted due to no activity on 2024/11/09 23:29
upstream WARNING in br_nf_local_in bridge netfilter -1 1 130d 126d 29/29 fixed on 2025/11/03 13:33
linux-5.15 WARNING in br_nf_local_in (2) -1 C error 8 182d 369d 0/3 auto-obsoleted due to no activity on 2025/10/22 18:27

Sample crash report:
------------[ cut here ]------------
WARNING: net/bridge/br_netfilter_hooks.c:602 at br_nf_local_in+0x40e/0x470 net/bridge/br_netfilter_hooks.c:602, CPU#1: ksoftirqd/1/23
Modules linked in:
CPU: 1 UID: 0 PID: 23 Comm: ksoftirqd/1 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:br_nf_local_in+0x40e/0x470 net/bridge/br_netfilter_hooks.c:602
Code: 38 69 eb f7 e9 4b fc ff ff 44 89 e1 80 e1 07 38 c1 0f 8c a8 fc ff ff 4c 89 e7 e8 1d 69 eb f7 e9 9b fc ff ff e8 d3 98 84 f7 90 <0f> 0b 90 48 89 df e8 b7 2b 00 00 e9 5b fd ff ff e8 bd 98 84 f7 90
RSP: 0000:ffffc900001d6f38 EFLAGS: 00010246
RAX: ffffffff8a3c21ed RBX: ffff8880792ba140 RCX: ffff88801d6ddac0
RDX: 0000000000000100 RSI: 0000000000000002 RDI: 0000000000000001
RBP: 0000000000000002 R08: ffff88807903e183 R09: 1ffff1100f207c30
R10: dffffc0000000000 R11: ffffed100f207c31 R12: 0000000000000000
R13: ffff8880792ba1a8 R14: 1ffff1100f257435 R15: ffff88807903e180
FS:  0000000000000000(0000) GS:ffff888125d07000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fa503fb1000 CR3: 0000000078d26000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 nf_hook_entry_hookfn include/linux/netfilter.h:158 [inline]
 nf_hook_slow+0xc5/0x220 net/netfilter/core.c:623
 nf_hook include/linux/netfilter.h:273 [inline]
 NF_HOOK+0x251/0x390 include/linux/netfilter.h:316
 br_handle_frame_finish+0x15c6/0x1c90 net/bridge/br_input.c:235
 br_nf_hook_thresh net/bridge/br_netfilter_hooks.c:-1 [inline]
 br_nf_pre_routing_finish+0x1364/0x1af0 net/bridge/br_netfilter_hooks.c:425
 NF_HOOK+0x61b/0x6b0 include/linux/netfilter.h:318
 br_nf_pre_routing+0xeb7/0x1470 net/bridge/br_netfilter_hooks.c:534
 nf_hook_entry_hookfn include/linux/netfilter.h:158 [inline]
 nf_hook_bridge_pre net/bridge/br_input.c:291 [inline]
 br_handle_frame+0x96e/0x14f0 net/bridge/br_input.c:442
 __netif_receive_skb_core+0x95f/0x2f90 net/core/dev.c:6026
 __netif_receive_skb_one_core net/core/dev.c:6137 [inline]
 __netif_receive_skb+0x72/0x380 net/core/dev.c:6252
 process_backlog+0x54f/0x1340 net/core/dev.c:6604
 __napi_poll+0xae/0x320 net/core/dev.c:7668
 napi_poll net/core/dev.c:7731 [inline]
 net_rx_action+0x64a/0xe00 net/core/dev.c:7883
 handle_softirqs+0x22b/0x7c0 kernel/softirq.c:626
 run_ksoftirqd+0x36/0x60 kernel/softirq.c:1067
 smpboot_thread_fn+0x542/0xa60 kernel/smpboot.c:160
 kthread+0x389/0x480 kernel/kthread.c:467
 ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
 </TASK>

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/01/11 00:32 linux-next f417b7ffcbef d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in br_nf_local_in
* Struck through repros no longer work on HEAD.