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BUG: soft lockup in neigh_timer_handler (4)

Status: closed as invalid on 2026/05/19 12:17
Subsystems: perf
[Documentation on labels]
First crash: 112d, last: 112d
▶ ▼ ✨ AI Jobs (1)
ID Workflow Result Correct Bug Created Started Finished Revision Error
d349c478-f282-4aa4-81fb-6a7aa5449874 assessment-security 💥 BUG: soft lockup in neigh_timer_handler (4) 2026/05/15 05:54 2026/05/15 05:54 2026/05/15 05:55 6ccb967e465e832a7bfd7a116ad00d52a0923a5d 
failed to run ["make" "KERNELVERSION=syzkaller" "KERNELRELEASE=syzkaller" "LOCALVERSION=-syzkaller" "-j" "32" "ARCH=x86_64" "CC=ccache clang" "LD=ld.lld" "O=/app/workdir/cache/build/c4b9e1b19037fd56d3...
truncated to first 200 bytes; open job for full error
▶ ▼ Similar bugs (18)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
android-5-10 BUG: soft lockup in neigh_timer_handler 1 2 1059d 1068d 0/2 auto-obsoleted due to no activity on 2023/11/22 05:43
linux-4.19 BUG: soft lockup in neigh_timer_handler 1 4 1344d 1603d 0/1 auto-obsoleted due to no activity on 2023/03/12 06:57
android-54 BUG: soft lockup in neigh_timer_handler (2) 1 5 429d 514d 0/2 auto-obsoleted due to no activity on 2025/08/13 05:16
linux-4.14 BUG: soft lockup in neigh_timer_handler 1 3 1613d 1656d 0/1 auto-closed as invalid on 2022/06/16 21:59
android-5-15 BUG: soft lockup in neigh_timer_handler 1 1 8d14h 8d14h 0/2 premoderation: reported on 2026/07/10 13:24
upstream BUG: soft lockup in neigh_timer_handler (3) batman 1 2 441d 441d 0/29 auto-obsoleted due to no activity on 2025/08/01 18:42
upstream BUG: soft lockup in neigh_timer_handler (2) net 1 2 541d 571d 0/29 closed as invalid on 2025/02/28 15:46
android-6-1 BUG: soft lockup in neigh_timer_handler 1 2 974d 996d 0/2 auto-obsoleted due to no activity on 2024/02/16 02:11
android-54 BUG: soft lockup in neigh_timer_handler 1 3 758d 770d 0/2 auto-obsoleted due to no activity on 2024/09/18 13:19
upstream BUG: soft lockup in neigh_timer_handler net 1 1 1092d 1066d 0/29 auto-obsoleted due to no activity on 2023/10/20 21:15
linux-6.6 INFO: rcu detected stall in neigh_timer_handler 1 1 137d 137d 0/2 auto-obsoleted due to no activity on 2026/06/12 03:02
upstream INFO: rcu detected stall in neigh_timer_handler (8) net 1 C done done 72 706d 766d 28/29 fixed on 2024/10/21 12:45
linux-5.15 INFO: rcu detected stall in neigh_timer_handler 1 1 307d 307d 0/3 auto-obsoleted due to no activity on 2025/12/23 11:36
linux-5.15 INFO: rcu detected stall in neigh_timer_handler (2) 1 2 144d 146d 0/3 auto-obsoleted due to no activity on 2026/06/04 18:05
linux-6.1 INFO: rcu detected stall in neigh_timer_handler (3) 1 1 276d 276d 0/3 auto-obsoleted due to no activity on 2026/01/23 04:30
upstream INFO: rcu detected stall in neigh_timer_handler (7) net 1 1 1923d 1923d 0/29 auto-closed as invalid on 2021/07/11 19:14
linux-6.1 INFO: rcu detected stall in neigh_timer_handler (2) 1 1 530d 530d 0/3 auto-obsoleted due to no activity on 2025/05/14 07:23
linux-6.1 INFO: rcu detected stall in neigh_timer_handler 1 4 661d 772d 0/3 auto-obsoleted due to no activity on 2025/01/03 05:12

Sample crash report:
watchdog: BUG: soft lockup - CPU#0 stuck for 111s! [syz.8.3440:21531]
Modules linked in:
irq event stamp: 7620853
hardirqs last  enabled at (7620852): [<ffffffff8baebf2e>] irqentry_exit+0x59e/0x620 kernel/entry/common.c:242
hardirqs last disabled at (7620853): [<ffffffff8baea93e>] sysvec_apic_timer_interrupt+0xe/0xc0 arch/x86/kernel/apic/apic.c:1056
softirqs last  enabled at (2261444): [<ffffffff8188041f>] __do_softirq kernel/softirq.c:656 [inline]
softirqs last  enabled at (2261444): [<ffffffff8188041f>] invoke_softirq kernel/softirq.c:496 [inline]
softirqs last  enabled at (2261444): [<ffffffff8188041f>] __irq_exit_rcu+0x5f/0x150 kernel/softirq.c:723
softirqs last disabled at (2261447): [<ffffffff8188041f>] __do_softirq kernel/softirq.c:656 [inline]
softirqs last disabled at (2261447): [<ffffffff8188041f>] invoke_softirq kernel/softirq.c:496 [inline]
softirqs last disabled at (2261447): [<ffffffff8188041f>] __irq_exit_rcu+0x5f/0x150 kernel/softirq.c:723
CPU: 0 UID: 0 PID: 21531 Comm: syz.8.3440 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:lock_acquire+0x20b/0x2e0 kernel/locking/lockdep.c:5872
Code: e9 30 ff ff ff e8 45 25 0d 0a f7 c3 00 02 00 00 0f 84 38 ff ff ff 65 48 8b 05 c1 a2 7a 11 48 3b 44 24 30 75 33 fb 48 83 c4 38 <5b> 41 5c 41 5d 41 5e 41 5f 5d c3 cc cc cc cc cc 48 8d 3d fe 78 73
RSP: 0018:ffffc90000006940 EFLAGS: 00000292
RAX: c71c7880c3d89a00 RBX: 0000000000000246 RCX: 0000000000000306
RDX: 0000000026b28eb2 RSI: ffffffff8e1699c5 RDI: ffffffff8c27c900
RBP: 0000000000000000 R08: ffffffff81d165d2 R09: ffffffff8e75e5e0
R10: dffffc0000000000 R11: fffff91ffff45e05 R12: 0000000000000002
R13: ffffffff8e75e5e0 R14: 0000000000000000 R15: 0000000000000000
FS:  00007f905ac906c0(0000) GS:ffff88812545d000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffd080a4db0 CR3: 000000008232e000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000200000000300 DR2: 0000000000000000
DR3: 0000200000000300 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
 rcu_read_lock include/linux/rcupdate.h:850 [inline]
 trace_call_bpf+0xe3/0xb70 kernel/trace/bpf_trace.c:-1
 perf_trace_run_bpf_submit+0x78/0x170 kernel/events/core.c:11329
 do_perf_trace_lock include/trace/events/lock.h:50 [inline]
 perf_trace_lock+0x32d/0x410 include/trace/events/lock.h:50
 __do_trace_lock_release include/trace/events/lock.h:69 [inline]
 trace_lock_release include/trace/events/lock.h:69 [inline]
 lock_release+0x392/0x3d0 kernel/locking/lockdep.c:5879
 rcu_lock_release include/linux/rcupdate.h:322 [inline]
 rcu_read_unlock include/linux/rcupdate.h:881 [inline]
 class_rcu_destructor include/linux/rcupdate.h:1193 [inline]
 unwind_next_frame+0x1aaa/0x23c0 arch/x86/kernel/unwind_orc.c:695
 arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122
 kasan_save_stack+0x3e/0x60 mm/kasan/common.c:57
 kasan_record_aux_stack+0xbd/0xd0 mm/kasan/generic.c:556
 __call_rcu_common kernel/rcu/tree.c:3131 [inline]
 call_rcu+0xee/0x890 kernel/rcu/tree.c:3251
 refdst_drop include/net/dst.h:272 [inline]
 skb_dst_drop include/net/dst.h:284 [inline]
 skb_release_head_state+0x71/0x360 net/core/skbuff.c:1177
 skb_release_all net/core/skbuff.c:1201 [inline]
 __kfree_skb+0x24/0x210 net/core/skbuff.c:1217
 kfree_skb_reason include/linux/skbuff.h:1322 [inline]
 kfree_skb include/linux/skbuff.h:1331 [inline]
 ip6gre_tunnel_xmit+0xb74/0xf70 net/ipv6/ip6_gre.c:912
 __netdev_start_xmit include/linux/netdevice.h:5325 [inline]
 netdev_start_xmit include/linux/netdevice.h:5334 [inline]
 xmit_one net/core/dev.c:3871 [inline]
 dev_hard_start_xmit+0x2d8/0x870 net/core/dev.c:3887
 sch_direct_xmit+0x251/0x4c0 net/sched/sch_generic.c:347
 __dev_xmit_skb net/core/dev.c:4186 [inline]
 __dev_queue_xmit+0x1550/0x3890 net/core/dev.c:4802
 NF_HOOK_COND include/linux/netfilter.h:307 [inline]
 ip6_output+0x340/0x550 net/ipv6/ip6_output.c:246
 dst_output include/net/dst.h:470 [inline]
 NF_HOOK include/linux/netfilter.h:318 [inline]
 ndisc_send_skb+0xd0b/0x1670 net/ipv6/ndisc.c:512
 ndisc_send_ns net/ipv6/ndisc.c:670 [inline]
 ndisc_solicit+0x374/0x670 net/ipv6/ndisc.c:761
 neigh_probe net/core/neighbour.c:1097 [inline]
 neigh_timer_handler+0xb50/0x11e0 net/core/neighbour.c:1192
 call_timer_fn+0x192/0x640 kernel/time/timer.c:1748
 expire_timers kernel/time/timer.c:1799 [inline]
 __run_timers kernel/time/timer.c:2373 [inline]
 __run_timer_base+0x652/0x8b0 kernel/time/timer.c:2385
 run_timer_base kernel/time/timer.c:2394 [inline]
 run_timer_softirq+0xb7/0x170 kernel/time/timer.c:2404
 handle_softirqs+0x22a/0x870 kernel/softirq.c:622
 __do_softirq kernel/softirq.c:656 [inline]
 invoke_softirq kernel/softirq.c:496 [inline]
 __irq_exit_rcu+0x5f/0x150 kernel/softirq.c:723
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:739
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline]
 sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1056
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:lock_acquire+0x20b/0x2e0 kernel/locking/lockdep.c:5872
Code: e9 30 ff ff ff e8 45 25 0d 0a f7 c3 00 02 00 00 0f 84 38 ff ff ff 65 48 8b 05 c1 a2 7a 11 48 3b 44 24 30 75 33 fb 48 83 c4 38 <5b> 41 5c 41 5d 41 5e 41 5f 5d c3 cc cc cc cc cc 48 8d 3d fe 78 73
RSP: 0018:ffffc900054eef60 EFLAGS: 00000296
RAX: c71c7880c3d89a00 RBX: 0000000000000246 RCX: 0000000080000004
RDX: 00000000fccf57e6 RSI: ffffffff8e1699c5 RDI: ffffffff8c27c900
RBP: 0000000000000000 R08: ffffffff81d165d2 R09: ffffffff8e75e5e0
R10: 6f6c5f646165725f R11: 64656863735f6b63 R12: 0000000000000002
R13: ffffffff8e75e5e0 R14: 0000000000000000 R15: 0000000000000000
 rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
 rcu_read_lock include/linux/rcupdate.h:850 [inline]
 trace_call_bpf+0xe3/0xb70 kernel/trace/bpf_trace.c:-1
 perf_trace_run_bpf_submit+0x78/0x170 kernel/events/core.c:11329
 do_perf_trace_lock include/trace/events/lock.h:50 [inline]
 perf_trace_lock+0x32d/0x410 include/trace/events/lock.h:50
 __do_trace_lock_release include/trace/events/lock.h:69 [inline]
 trace_lock_release include/trace/events/lock.h:69 [inline]
 lock_release+0x392/0x3d0 kernel/locking/lockdep.c:5879
 rcu_lock_release include/linux/rcupdate.h:322 [inline]
 rcu_read_unlock_sched include/linux/rcupdate.h:972 [inline]
 pfn_valid+0x3b2/0x480 include/linux/mmzone.h:2207
 page_table_check_set+0x25/0x610 mm/page_table_check.c:105
 page_table_check_ptes_set include/linux/page_table_check.h:83 [inline]
 set_ptes include/linux/pgtable.h:413 [inline]
 __copy_present_ptes mm/memory.c:1115 [inline]
 copy_present_ptes mm/memory.c:1194 [inline]
 copy_pte_range mm/memory.c:1317 [inline]
 copy_pmd_range+0x4f5a/0x8050 mm/memory.c:1405
 copy_pud_range mm/memory.c:1442 [inline]
 copy_p4d_range mm/memory.c:1466 [inline]
 copy_page_range+0xbe8/0x11f0 mm/memory.c:1552
 dup_mmap+0xf40/0x1d90 mm/mmap.c:1841
 dup_mm kernel/fork.c:1531 [inline]
 copy_mm+0x13b/0x4a0 kernel/fork.c:1583
 copy_process+0x18b6/0x3cd0 kernel/fork.c:2223
 kernel_clone+0x248/0x8e0 kernel/fork.c:2653
 __do_sys_clone kernel/fork.c:2794 [inline]
 __se_sys_clone kernel/fork.c:2778 [inline]
 __x64_sys_clone+0x1b6/0x230 kernel/fork.c:2778
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f9059d9c799
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:00007f905ac8ffd8 EFLAGS: 00000246 ORIG_RAX: 0000000000000038
RAX: ffffffffffffffda RBX: 00007f905a015fa0 RCX: 00007f9059d9c799
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007f9059e32c99 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f905a016038 R14: 00007f905a015fa0 R15: 00007ffd23bdc748
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 5195 Comm: udevd Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:rb_next+0x0/0xe0 lib/rbtree.c:464
Code: c4 28 5b 41 5c 41 5d 41 5e 41 5f 5d c3 cc cc cc cc cc 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 <f3> 0f 1e fa 41 57 41 56 53 48 89 fb 49 bf 00 00 00 00 00 fc ff df
RSP: 0018:ffffc90000a08d00 EFLAGS: 00000006
RAX: ffffffff8baa8502 RBX: ffff8880b8728350 RCX: ffff8880576f1e80
RDX: 0000000000010000 RSI: ffff8880b8728c28 RDI: ffff8880b8728c28
RBP: 1ffff110170e5185 R08: ffffffff9a4eace3 R09: 1ffffffff349d59c
R10: dffffc0000000000 R11: fffffbfff349d59d R12: ffff8880b8728358
R13: dffffc0000000000 R14: ffff8880b8728c28 R15: 1ffff110170e506b
FS:  00007fb4fa389880(0000) GS:ffff88812555d000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f6bed8847e8 CR3: 00000000577f4000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 rb_erase_cached include/linux/rbtree.h:152 [inline]
 timerqueue_del+0x8a/0x100 lib/timerqueue.c:57
 __remove_hrtimer kernel/time/hrtimer.c:1122 [inline]
 __run_hrtimer kernel/time/hrtimer.c:1765 [inline]
 __hrtimer_run_queues+0x37b/0xcc0 kernel/time/hrtimer.c:1849
 hrtimer_interrupt+0x42b/0x1010 kernel/time/hrtimer.c:1911
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1045 [inline]
 __sysvec_apic_timer_interrupt+0x102/0x460 arch/x86/kernel/apic/apic.c:1062
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline]
 sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1056
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:console_trylock_spinning kernel/printk/printk.c:2039 [inline]
RIP: 0010:vprintk_emit+0x45d/0x560 kernel/printk/printk.c:2478
Code: 0f 84 44 ff ff ff e8 d2 2d 21 00 fb eb 44 e8 ca 2d 21 00 e8 25 3e 0a 0a 4d 85 f6 74 94 e8 bb 2d 21 00 fb 48 c7 c7 20 0a 75 8e <31> f6 ba 01 00 00 00 31 c9 41 b8 01 00 00 00 45 31 c9 53 e8 cb 16
RSP: 0018:ffffc9000213f8a0 EFLAGS: 00000293
RAX: ffffffff81a47475 RBX: ffffffff81a472ef RCX: ffff8880576f1e80
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff8e750a20
RBP: ffffc9000213f950 R08: ffffffff9011b2b7 R09: 1ffffffff2023656
R10: dffffc0000000000 R11: fffffbfff2023657 R12: 0000000000000000
R13: 0000000000000048 R14: 0000000000000200 R15: 1ffff92000427f18
 devkmsg_emit+0xe4/0x140 kernel/printk/printk.c:733
 devkmsg_write+0x31c/0x400 kernel/printk/printk.c:796
 do_iter_readv_writev+0x619/0x8c0 fs/read_write.c:-1
 vfs_writev+0x33c/0x990 fs/read_write.c:1059
 do_writev+0x154/0x2e0 fs/read_write.c:1105
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fb4f9ca7407
Code: 48 89 fa 4c 89 df e8 38 aa 00 00 8b 93 08 03 00 00 59 5e 48 83 f8 fc 74 1a 5b c3 0f 1f 84 00 00 00 00 00 48 8b 44 24 10 0f 05 <5b> c3 0f 1f 80 00 00 00 00 83 e2 39 83 fa 08 75 de e8 23 ff ff ff
RSP: 002b:00007fff3d9c5790 EFLAGS: 00000202 ORIG_RAX: 0000000000000014
RAX: ffffffffffffffda RBX: 00007fb4fa389880 RCX: 00007fb4f9ca7407
RDX: 0000000000000005 RSI: 00007fff3d9c5850 RDI: 0000000000000005
RBP: 00007fff3d9c5980 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 00007fff3d9c5850
R13: 00007fff3d9c58e0 R14: 0000000000000000 R15: 00007fff3d9c58c0
 </TASK>

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/03/28 11:06 bpf c369299895a5 356bdfc9 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-bpf-kasan-gce BUG: soft lockup in neigh_timer_handler
* Struck through repros no longer work on HEAD.