BUG: soft lockup in neigh_timer_handler

Status: auto-obsoleted due to no activity on 2026/10/08 13:26
Reported-by: syzbot+d433a4a3542a1f1ba457@syzkaller.appspotmail.com
First crash: 97d, last: 97d
▶ ▼ Similar bugs (22)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream BUG: soft lockup in neigh_timer_handler (4) perf 1 1 201d 201d 0/29 closed as invalid on 2026/05/19 12:17
android-5-10 BUG: soft lockup in neigh_timer_handler (2) 1 1 19d 19d 0/2 premoderation: reported on 2026/09/26 09:04
android-5-10 BUG: soft lockup in neigh_timer_handler 1 2 1148d 1156d 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 1433d 1692d 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 518d 603d 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 1702d 1745d 0/1 auto-closed as invalid on 2022/06/16 21:59
upstream BUG: soft lockup in neigh_timer_handler (3) batman 1 2 530d 530d 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 630d 660d 0/29 closed as invalid on 2025/02/28 15:46
android-6-1 BUG: soft lockup in neigh_timer_handler 1 2 1062d 1084d 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 847d 859d 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 1181d 1155d 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 225d 225d 0/2 auto-obsoleted due to no activity on 2026/06/12 03:02
linux-6.1 INFO: rcu detected stall in neigh_timer_handler (4) 1 1 1d00h 1d00h 0/3 upstream: reported on 2026/10/14 22:04
upstream INFO: rcu detected stall in neigh_timer_handler (8) net 1 syz, C done done 72 795d 855d 28/29 fixed on 2024/10/21 12:45
linux-5.15 INFO: rcu detected stall in neigh_timer_handler 1 1 396d 396d 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 (3) 1 5 13h00m 69d 0/3 upstream: reported on 2026/08/07 01:39
linux-6.6 INFO: rcu detected stall in neigh_timer_handler (2) 1 1 82d 82d 0/2 upstream: reported on 2026/07/25 18:11
linux-5.15 INFO: rcu detected stall in neigh_timer_handler (2) 1 2 233d 235d 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 365d 365d 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 2012d 2012d 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 619d 619d 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 750d 861d 0/3 auto-obsoleted due to no activity on 2025/01/03 05:12

Sample crash report:
watchdog: BUG: soft lockup - CPU#1 stuck for 246s! [syz.3.1516:5853]
Modules linked in:
CPU: 1 PID: 5853 Comm: syz.3.1516 Tainted: G        W         syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
RIP: 0010:check_kcov_mode kernel/kcov.c:172 [inline]
RIP: 0010:__sanitizer_cov_trace_pc+0x2e/0x60 kernel/kcov.c:206
Code: 48 8b 45 08 65 48 8b 0d e0 b7 98 7e 65 8b 15 e1 b7 98 7e 81 e2 00 01 ff 00 74 11 81 fa 00 01 00 00 75 35 83 b9 5c 0b 00 00 00 <74> 2c 8b 91 38 0b 00 00 83 fa 02 75 21 48 8b 91 40 0b 00 00 48 8b
RSP: 0018:ffffc900001d04d0 EFLAGS: 00000246
RAX: ffffffff84377736 RBX: 0000000000000000 RCX: ffff88810c6e0000
RDX: 0000000000000100 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc900001d04d0 R08: ffff8881096fa040 R09: ffffc900001d0630
R10: dffffc0000000000 R11: fffff5200003a0ca R12: ffff8881096fa110
R13: dffffc0000000000 R14: ffff8881096fa100 R15: 1ffff110212df432
FS:  00007fee980de6c0(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000100000001 CR3: 000000014420d000 CR4: 00000000003506a0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 ip6_packet_match net/ipv6/netfilter/ip6_tables.c:80 [inline]
 ip6t_do_table+0x836/0x1510 net/ipv6/netfilter/ip6_tables.c:308
 ip6table_raw_hook+0x25/0x30 net/ipv6/netfilter/ip6table_raw.c:39
 nf_hook_entry_hookfn include/linux/netfilter.h:143 [inline]
 nf_hook_slow+0xbc/0x200 net/netfilter/core.c:590
 nf_hook include/linux/netfilter.h:260 [inline]
 __ip6_local_out net/ipv6/output_core.c:149 [inline]
 ip6_local_out+0x365/0x3c0 net/ipv6/output_core.c:159
 ip6_send_skb net/ipv6/ip6_output.c:1885 [inline]
 ip6_push_pending_frames+0x17d/0x2d0 net/ipv6/ip6_output.c:1906
 icmpv6_push_pending_frames+0x2f4/0x4e0 net/ipv6/icmp.c:311
 icmp6_send+0x114e/0x1750 net/ipv6/icmp.c:630
 __icmpv6_send include/linux/icmpv6.h:28 [inline]
 icmpv6_send include/linux/icmpv6.h:49 [inline]
 ip6_link_failure+0x86/0x340 net/ipv6/route.c:2795
 dst_link_failure include/net/dst.h:423 [inline]
 ndisc_error_report+0x9b/0xc0 net/ipv6/ndisc.c:717
 neigh_invalidate+0x274/0x4d0 net/core/neighbour.c:1001
 neigh_timer_handler+0x86f/0xe80 net/core/neighbour.c:1088
 call_timer_fn+0x38/0x290 kernel/time/timer.c:1459
 expire_timers kernel/time/timer.c:1504 [inline]
 __run_timers+0x637/0x9a0 kernel/time/timer.c:1775
 run_timer_softirq+0x6a/0xf0 kernel/time/timer.c:1788
 handle_softirqs+0x250/0x560 kernel/softirq.c:583
 __do_softirq kernel/softirq.c:621 [inline]
 invoke_softirq kernel/softirq.c:443 [inline]
 __irq_exit_rcu+0x52/0xf0 kernel/softirq.c:670
 irq_exit_rcu+0x9/0x10 kernel/softirq.c:682
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline]
 sysvec_apic_timer_interrupt+0xa9/0xc0 arch/x86/kernel/apic/apic.c:1108
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1b/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:preempt_schedule_irq+0xa5/0x120 kernel/sched/core.c:6942
Code: 44 24 20 00 02 00 00 43 c6 44 37 04 f8 74 0b 0f 0b 48 f7 03 08 00 00 00 74 4d bf 01 00 00 00 e8 c1 7b 95 fc fb bf 01 00 00 00 <e8> 76 e4 ff ff fa bf 01 00 00 00 e8 5b 7d 95 fc 65 48 8b 1d 13 27
RSP: 0018:ffffc90001957da0 EFLAGS: 00000246
RAX: 1ffff110218dc156 RBX: ffffc90001957e68 RCX: ffffffff870cbf00
RDX: 1ffffffff0e18808 RSI: 0000000000000000 RDI: 0000000000000001
RBP: ffffc90001957e18 R08: ffffffff870c4048 R09: ffffffff870c4058
R10: ffffffff870c4043 R11: 1ffffffff0e18808 R12: 0000000000000000
R13: 0000000000000000 R14: dffffc0000000000 R15: 1ffff9200032afb4
 irqentry_exit_cond_resched+0x29/0x30 kernel/entry/common.c:398
 irqentry_exit+0x37/0x40 kernel/entry/common.c:432
 sysvec_apic_timer_interrupt+0x64/0xc0 arch/x86/kernel/apic/apic.c:1108
 asm_sysvec_apic_timer_interrupt+0x1b/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:__syscall_enter_from_user_work kernel/entry/common.c:93 [inline]
RIP: 0010:syscall_enter_from_user_mode+0xc/0x30 kernel/entry/common.c:114
Code: 89 e5 e8 e7 fe ff ff 5d c3 00 00 cc cc 00 55 48 89 e5 5d c3 66 2e 0f 1f 84 00 00 00 00 00 48 89 f0 fb 65 48 8b 0d 34 6b 54 7b <48> 8b 71 08 40 f6 c6 3f 74 0a 55 48 89 e5 e8 c1 6a ab fc 5d c3 66
RSP: 0018:ffffc90001957f18 EFLAGS: 00000282
RAX: 00000000000000ca RBX: ffffc90001957f20 RCX: ffff88810c6e0000
RDX: 0000000000000000 RSI: 00000000000000ca RDI: ffffc90001957f58
RBP: ffffc90001957f48 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: ffffc90001957f58 R15: 0000000000000000
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fee996a5e59
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:00007fee980de0e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: ffffffffffffffda RBX: 00007fee9992e098 RCX: 00007fee996a5e59
RDX: 00000000000f4240 RSI: 0000000000000081 RDI: 00007fee9992e09c
RBP: 00007fee9992e090 R08: 0037989b0b70994c R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fee9992e128 R14: 00007ffc7063bd80 R15: 00007ffc7063be68
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 5851 Comm: syz.1.1515 Tainted: G        W         syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
RIP: 0010:update_stack_state+0x418/0x490 arch/x86/kernel/unwind_frame.c:258
Code: 48 8b 5d d0 48 83 c3 48 48 89 d8 48 c1 e8 03 42 80 3c 28 00 74 08 48 89 df e8 b4 65 77 00 4c 89 33 43 80 3c 2c 00 48 8b 5d c8 <74> 08 48 89 df e8 fe 64 77 00 b0 01 48 83 3b 00 0f 85 82 fe ff ff
RSP: 0018:ffffc90000006840 EFLAGS: 00000046
RAX: 1ffff92000000d41 RBX: ffffc90000006a00 RCX: ffffc90000967f01
RDX: ffffc90000967f10 RSI: 1ffff92000000d39 RDI: ffffc900000069e8
RBP: ffffc900000068f0 R08: ffffc90000006a01 R09: ffffc900000069c0
R10: dffffc0000000000 R11: fffff52000000d44 R12: 1ffff92000000d40
R13: dffffc0000000000 R14: ffffffff84add4ec R15: ffffc90000006a18
FS:  00007f0a681166c0(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f86f4d89f08 CR3: 0000000145702000 CR4: 00000000003506b0
DR0: 0000000000000000 DR1: 0000200000000300 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 unwind_next_frame+0x39e/0x660 arch/x86/kernel/unwind_frame.c:316
 perf_callchain_kernel+0x400/0x6c0 arch/x86/events/core.c:2783
 get_perf_callchain+0x356/0x460 kernel/events/callchain.c:200
 perf_callchain kernel/events/core.c:7481 [inline]
 perf_prepare_sample+0x352/0x1a30 kernel/events/core.c:7508
 __perf_event_output kernel/events/core.c:7677 [inline]
 perf_event_output_forward+0xd1/0x1a0 kernel/events/core.c:7697
 __perf_event_overflow+0x215/0x3d0 kernel/events/core.c:9365
 perf_swevent_hrtimer+0x3c2/0x550 kernel/events/core.c:10784
 __run_hrtimer kernel/time/hrtimer.c:1689 [inline]
 __hrtimer_run_queues+0x38a/0x890 kernel/time/hrtimer.c:1753
 hrtimer_interrupt+0x3ad/0x8c0 kernel/time/hrtimer.c:1815
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1097 [inline]
 __sysvec_apic_timer_interrupt+0xfa/0x3e0 arch/x86/kernel/apic/apic.c:1114
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline]
 sysvec_apic_timer_interrupt+0x53/0xc0 arch/x86/kernel/apic/apic.c:1108
 asm_sysvec_apic_timer_interrupt+0x1b/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:ip6_ignore_linkdown include/net/addrconf.h:449 [inline]
RIP: 0010:find_match+0xed/0xf30 net/ipv6/route.c:744
Code: 7d fd 48 8b 1b 48 85 db 0f 84 90 0b 00 00 48 81 c3 08 04 00 00 48 89 d8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df 0f b6 04 08 <84> c0 0f 85 ce 0b 00 00 8b 1b 31 ff 89 de e8 d0 e0 3d fd 85 db 74
RSP: 0018:ffffc90000007378 EFLAGS: 00000a06
RAX: 0000000000000000 RBX: ffff88812735f408 RCX: dffffc0000000000
RDX: 0000000000000100 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc90000007430 R08: ffffc900000076a0 R09: ffffc900000076b0
R10: dffffc0000000000 R11: fffff52000000ef6 R12: 0000000000000001
R13: 1ffff110251af996 R14: 0000000000000000 R15: 0000000000000003
 __find_rr_leaf+0x244/0x9b0 net/ipv6/route.c:832
 find_rr_leaf net/ipv6/route.c:853 [inline]
 rt6_select net/ipv6/route.c:897 [inline]
 fib6_table_lookup+0x2f7/0x9e0 net/ipv6/route.c:2190
 ip6_pol_route+0x152/0x1170 net/ipv6/route.c:2226
 ip6_pol_route_input+0x56/0x80 net/ipv6/route.c:2284
 pol_lookup_func include/net/ip6_fib.h:592 [inline]
 fib6_rule_lookup+0x20a/0x5d0 net/ipv6/fib6_rules.c:115
 ip6_route_input_lookup net/ipv6/route.c:2296 [inline]
 ip6_route_input+0x5fd/0x8c0 net/ipv6/route.c:2592
 ip6_rcv_finish_core net/ipv6/ip6_input.c:66 [inline]
 ip6_rcv_finish+0x156/0x360 net/ipv6/ip6_input.c:77
 NF_HOOK include/linux/netfilter.h:305 [inline]
 ipv6_rcv+0xed/0x230 net/ipv6/ip6_input.c:300
 __netif_receive_skb_one_core net/core/dev.c:5559 [inline]
 __netif_receive_skb+0xc8/0x280 net/core/dev.c:5673
 process_backlog+0x351/0x600 net/core/dev.c:6550
 __napi_poll+0xbb/0x580 net/core/dev.c:7109
 napi_poll net/core/dev.c:7176 [inline]
 net_rx_action+0x37f/0x910 net/core/dev.c:7266
 handle_softirqs+0x250/0x560 kernel/softirq.c:583
 __do_softirq kernel/softirq.c:621 [inline]
 invoke_softirq kernel/softirq.c:443 [inline]
 __irq_exit_rcu+0x52/0xf0 kernel/softirq.c:670
 irq_exit_rcu+0x9/0x10 kernel/softirq.c:682
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline]
 sysvec_apic_timer_interrupt+0xa9/0xc0 arch/x86/kernel/apic/apic.c:1108
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1b/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:cmpxchg_double_slab+0xa9/0x150 mm/slub.c:490
Code: 9f ff 65 8b 05 40 b4 59 7e 85 c0 74 79 b0 01 f7 45 c0 00 02 00 00 74 40 fb eb 3d 4c 89 f9 4c 89 e8 4c 89 e2 f0 49 0f c7 4e 20 <b0> 01 75 26 eb 28 49 0f ba 36 00 bf 01 00 00 00 e8 42 0a 9f ff 65
RSP: 0018:ffffc900009677a8 EFLAGS: 00000242
RAX: ffff88814a0b5640 RBX: ffff88814a0b58c0 RCX: 00000000800c0009
RDX: 00000000800c000a RSI: ffffea0005282d40 RDI: ffff8881081ab800
RBP: ffffc900009677e8 R08: ffff88814a0b58c0 R09: 00000000800c0009
R10: dffffc0000000000 R11: fffff5200012cf0c R12: 00000000800c000a
R13: ffff88814a0b5640 R14: ffffea0005282d40 R15: 00000000800c0009
 __slab_free+0x97/0x290 mm/slub.c:3377
 do_slab_free mm/slub.c:3514 [inline]
 ___cache_free+0x104/0x120 mm/slub.c:3535
 qlink_free+0x4d/0x90 mm/kasan/quarantine.c:157
 qlist_free_all+0x5f/0xb0 mm/kasan/quarantine.c:176
 kasan_quarantine_reduce+0x14a/0x170 mm/kasan/quarantine.c:283
 __kasan_slab_alloc+0x2f/0xe0 mm/kasan/common.c:443
 kasan_slab_alloc include/linux/kasan.h:217 [inline]
 slab_post_alloc_hook+0x4f/0x2b0 mm/slab.h:550
 slab_alloc_node mm/slub.c:3245 [inline]
 slab_alloc mm/slub.c:3255 [inline]
 kmem_cache_alloc+0xf7/0x260 mm/slub.c:3260
 sk_prot_alloc+0x5f/0x320 net/core/sock.c:1862
 sk_alloc+0x38/0x430 net/core/sock.c:1928
 tipc_sk_create+0xdb/0x1d10 net/tipc/socket.c:488
 __sock_create+0x38d/0x7a0 net/socket.c:1485
 sock_create net/socket.c:1541 [inline]
 __sys_socketpair+0x218/0x590 net/socket.c:1645
 __do_sys_socketpair net/socket.c:1694 [inline]
 __se_sys_socketpair net/socket.c:1691 [inline]
 __x64_sys_socketpair+0x9b/0xb0 net/socket.c:1691
 x64_sys_call+0x36/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:54
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f0a696bce59
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:00007f0a68116028 EFLAGS: 00000246 ORIG_RAX: 0000000000000035
RAX: ffffffffffffffda RBX: 00007f0a69944fa0 RCX: 00007f0a696bce59
RDX: 0000000000000000 RSI: 0000000000000002 RDI: 000000000000001e
RBP: 00007f0a69752e6f R08: 0000000000000000 R09: 0000000000000000
R10: 00002000000000c0 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f0a69945038 R14: 00007f0a69944fa0 R15: 00007ffd431f5be8
 </TASK>

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/07/10 13:23 android13-5.15-lts 7e958e2b7c41 4167ee25 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15-perf BUG: soft lockup in neigh_timer_handler
* Struck through repros no longer work on HEAD.