syzbot

 sign-in | mailing list | source | docs
🐞 Open [1460]
≡ Subsystems
🐞 Fixed [6837]
🐞 Invalid [17727]
⬇ Missing Backports [227]
≡ Crashes
Kernel Health Bugs/Month Bug Lifetimes Fuzzing
Total Repo Heatmap Subsystems Heatmap
💬 Send us feedback

BUG: soft lockup in neigh_periodic_work

Status: closed as invalid on 2025/01/28 16:26
Subsystems: net
[Documentation on labels]
First crash: 403d, last: 371d
▶ ▼ Similar bugs (6)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: rcu detected stall in neigh_periodic_work (5) net 1 syz error 1 9d15h 5d15h 0/29 upstream: reported syz repro on 2026/01/02 09:02
upstream INFO: rcu detected stall in neigh_periodic_work (2) net 1 C error 2 668d 840d 0/29 closed as invalid on 2024/03/13 18:06
upstream INFO: rcu detected stall in neigh_periodic_work (4) net 1 1 250d 250d 0/29 auto-obsoleted due to no activity on 2025/07/31 09:55
upstream INFO: rcu detected stall in neigh_periodic_work (3) net 1 2 606d 625d 0/29 auto-obsoleted due to no activity on 2024/08/09 21:19
upstream INFO: rcu detected stall in neigh_periodic_work net 1 1 1035d 1035d 0/29 auto-obsoleted due to no activity on 2023/06/07 17:40
linux-6.1 INFO: rcu detected stall in neigh_periodic_work origin:upstream 1 syz 1 21d 217d 0/3 upstream: reported syz repro on 2025/06/04 08:32

Sample crash report:
watchdog: BUG: soft lockup - CPU#1 stuck for 223s! [kworker/1:2:5305]
Modules linked in:
irq event stamp: 126061
hardirqs last  enabled at (126060): [<ffffffff8b2db5cb>] irqentry_exit+0x3b/0x90 kernel/entry/common.c:357
hardirqs last disabled at (126061): [<ffffffff8b2d9d4e>] sysvec_apic_timer_interrupt+0xe/0xc0 arch/x86/kernel/apic/apic.c:1049
softirqs last  enabled at (126032): [<ffffffff89080c67>] neigh_periodic_work+0x767/0xcb0 net/core/neighbour.c:968
softirqs last disabled at (126034): [<ffffffff89080c87>] neigh_periodic_work+0x787/0xcb0 net/core/neighbour.c:970
CPU: 1 UID: 0 PID: 5305 Comm: kworker/1:2 Not tainted 6.12.0-syzkaller-10740-g509f806f7f70 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Workqueue: events_power_efficient neigh_periodic_work
RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline]
RIP: 0010:_raw_spin_unlock_irqrestore+0x31/0x80 kernel/locking/spinlock.c:194
Code: f5 53 48 8b 74 24 10 48 89 fb 48 83 c7 18 e8 76 30 3b f6 48 89 df e8 be af 3b f6 f7 c5 00 02 00 00 75 23 9c 58 f6 c4 02 75 37 <bf> 01 00 00 00 e8 45 a4 2c f6 65 8b 05 26 9f d3 74 85 c0 74 16 5b
RSP: 0018:ffffc9000456fa10 EFLAGS: 00000246
RAX: 0000000000000006 RBX: ffff88807c3ce610 RCX: 1ffffffff2dd36b2
RDX: 0000000000000000 RSI: ffffffff8b6ce000 RDI: ffffffff8bd1d780
RBP: 0000000000000296 R08: 0000000000000001 R09: fffffbfff2dd01a0
R10: ffffffff96e80d07 R11: 0000000000000003 R12: 1ffff920008adf47
R13: ffff8880252473c0 R14: ffff88807c3ce670 R15: ffff88807c3ce678
FS:  0000000000000000(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f96c730cab8 CR3: 000000000df7e000 CR4: 0000000000350ef0
Call Trace:
 <IRQ>
 </IRQ>
 <TASK>
 spin_unlock_irqrestore include/linux/spinlock.h:406 [inline]
 ref_tracker_free+0x36f/0x820 lib/ref_tracker.c:270
 netdev_tracker_free include/linux/netdevice.h:4156 [inline]
 netdev_put include/linux/netdevice.h:4173 [inline]
 netdev_put include/linux/netdevice.h:4169 [inline]
 neigh_destroy+0x339/0x630 net/core/neighbour.c:870
 neigh_release include/net/neighbour.h:442 [inline]
 neigh_cleanup_and_release net/core/neighbour.c:121 [inline]
 neigh_periodic_work+0x743/0xcb0 net/core/neighbour.c:959
 process_one_work+0x9c8/0x1ba0 kernel/workqueue.c:3229
 process_scheduled_works kernel/workqueue.c:3310 [inline]
 worker_thread+0x6c8/0xf00 kernel/workqueue.c:3391
 kthread+0x2c4/0x3a0 kernel/kthread.c:389
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 7568 Comm: syz.4.607 Not tainted 6.12.0-syzkaller-10740-g509f806f7f70 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
RIP: 0010:queued_write_lock_slowpath+0x179/0x330 kernel/locking/qrwlock.c:85
Code: 03 3d 00 01 00 00 74 37 48 b8 00 00 00 00 00 fc ff df 48 89 d9 48 89 da 48 c1 e9 03 83 e2 07 48 01 c1 83 c2 03 f3 90 0f b6 01 <38> c2 7c 08 84 c0 0f 85 5f 01 00 00 8b 03 3d 00 01 00 00 75 e6 48
RSP: 0018:ffffc900000075f8 EFLAGS: 00000206
RAX: 0000000000000000 RBX: ffffffff900d8300 RCX: fffffbfff201b060
RDX: 0000000000000003 RSI: 0000000000000004 RDI: ffffffff900d8300
RBP: 1ffff92000000ec1 R08: 0000000000000001 R09: fffffbfff201b060
R10: ffffffff900d8303 R11: 0000000000000004 R12: ffffffff900d8304
R13: 0000000000000003 R14: fffffbfff201b060 R15: ffffc90000007638
FS:  00007fb8846de6c0(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f7a0390cab8 CR3: 000000007cb1e000 CR4: 0000000000350ef0
Call Trace:
 <NMI>
 </NMI>
 <IRQ>
 queued_write_lock include/asm-generic/qrwlock.h:101 [inline]
 do_raw_write_lock+0x1d4/0x3a0 kernel/locking/spinlock_debug.c:211
 ___neigh_create+0x9e4/0x2970 net/core/neighbour.c:641
 ip6_finish_output2+0x1120/0x2070 net/ipv6/ip6_output.c:132
 __ip6_finish_output net/ipv6/ip6_output.c:215 [inline]
 ip6_finish_output+0x3f9/0x1360 net/ipv6/ip6_output.c:226
 NF_HOOK_COND include/linux/netfilter.h:303 [inline]
 ip6_output+0x1f8/0x540 net/ipv6/ip6_output.c:247
 dst_output include/net/dst.h:450 [inline]
 NF_HOOK include/linux/netfilter.h:314 [inline]
 ndisc_send_skb+0xa69/0x1c50 net/ipv6/ndisc.c:511
 ndisc_send_rs+0x129/0x670 net/ipv6/ndisc.c:721
 addrconf_rs_timer+0x407/0x840 net/ipv6/addrconf.c:4061
 call_timer_fn+0x1a3/0x610 kernel/time/timer.c:1793
 expire_timers kernel/time/timer.c:1844 [inline]
 __run_timers+0x6e8/0x930 kernel/time/timer.c:2418
 __run_timer_base kernel/time/timer.c:2430 [inline]
 __run_timer_base kernel/time/timer.c:2422 [inline]
 run_timer_base+0x114/0x190 kernel/time/timer.c:2439
 run_timer_softirq+0x1a/0x40 kernel/time/timer.c:2449
 handle_softirqs+0x216/0x8f0 kernel/softirq.c:554
 __do_softirq kernel/softirq.c:588 [inline]
 invoke_softirq kernel/softirq.c:428 [inline]
 __irq_exit_rcu+0x109/0x170 kernel/softirq.c:655
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:671
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049 [inline]
 sysvec_apic_timer_interrupt+0xa4/0xc0 arch/x86/kernel/apic/apic.c:1049
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:csd_lock_wait kernel/smp.c:340 [inline]
RIP: 0010:smp_call_function_many_cond+0x45d/0x1300 kernel/smp.c:884
Code: 4d 48 b8 00 00 00 00 00 fc ff df 4d 89 f4 4c 89 f5 49 c1 ec 03 83 e5 07 49 01 c4 83 c5 03 e8 ca 0d 0c 00 f3 90 41 0f b6 04 24 <40> 38 c5 7c 08 84 c0 0f 85 a7 0c 00 00 8b 43 08 31 ff 83 e0 01 41
RSP: 0018:ffffc90003917a30 EFLAGS: 00000246
RAX: 0000000000000000 RBX: ffff8880b8744a40 RCX: ffffc9000d84b000
RDX: 0000000000080000 RSI: ffffffff8182b6b6 RDI: 0000000000000005
RBP: 0000000000000003 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000001 R12: ffffed10170e8949
R13: 0000000000000001 R14: ffff8880b8744a48 R15: ffff8880b863fe40
 on_each_cpu_cond_mask+0x40/0x90 kernel/smp.c:1051
 kill_bdev block/bdev.c:90 [inline]
 blkdev_flush_mapping+0xf1/0x290 block/bdev.c:671
 blkdev_put_whole+0xc4/0xf0 block/bdev.c:678
 bdev_release+0x47e/0x6d0 block/bdev.c:1103
 blkdev_release+0x15/0x20 block/fops.c:635
 __fput+0x3fb/0xb60 fs/file_table.c:450
 task_work_run+0x151/0x250 kernel/task_work.c:239
 get_signal+0x1d3/0x26c0 kernel/signal.c:2789
 arch_do_signal_or_restart+0x90/0x7e0 arch/x86/kernel/signal.c:337
 exit_to_user_mode_loop kernel/entry/common.c:111 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0x150/0x2a0 kernel/entry/common.c:218
 do_syscall_64+0xda/0x250 arch/x86/entry/common.c:89
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fb883980849
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fb8846de058 EFLAGS: 00000246 ORIG_RAX: 0000000000000028
RAX: 0000000000340000 RBX: 00007fb883b45fa0 RCX: 00007fb883980849
RDX: 0000000000000000 RSI: 0000000000000005 RDI: 0000000000000005
RBP: 00007fb8839f3986 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000024002de8 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007fb883b45fa0 R15: 00007fff9504cec8
 </TASK>

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/11/30 08:24 upstream 509f806f7f70 68914665 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root BUG: soft lockup in neigh_periodic_work
2025/01/01 10:28 upstream ccb98ccef0e5 d3ccff63 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root INFO: rcu detected stall in neigh_periodic_work
* Struck through repros no longer work on HEAD.