BUG: soft lockup in neigh_timer_handler

Status: auto-obsoleted due to no activity on 2023/11/22 05:43
Reported-by: syzbot+020e7bd11e6f3fea72f2@syzkaller.appspotmail.com
First crash: 1075d, last: 1066d
▶ ▼ Similar bugs (19)
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 119d 119d 0/29 closed as invalid on 2026/05/19 12:17
linux-4.19 BUG: soft lockup in neigh_timer_handler 1 4 1351d 1610d 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 436d 521d 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 1620d 1663d 0/1 auto-closed as invalid on 2022/06/16 21:59
android-5-15 BUG: soft lockup in neigh_timer_handler 1 1 15d 15d 0/2 premoderation: reported on 2026/07/10 13:24
upstream BUG: soft lockup in neigh_timer_handler (3) batman 1 2 448d 449d 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 548d 578d 0/29 closed as invalid on 2025/02/28 15:46
android-6-1 BUG: soft lockup in neigh_timer_handler 1 2 981d 1003d 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 765d 777d 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 1099d 1073d 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 144d 144d 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 713d 773d 28/29 fixed on 2024/10/21 12:45
linux-5.15 INFO: rcu detected stall in neigh_timer_handler 1 1 314d 314d 0/3 auto-obsoleted due to no activity on 2025/12/23 11:36
linux-6.6 INFO: rcu detected stall in neigh_timer_handler (2) 1 1 10h30m 10h29m 0/2 upstream: reported on 2026/07/25 18:11
linux-5.15 INFO: rcu detected stall in neigh_timer_handler (2) 1 2 151d 153d 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 284d 284d 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 1930d 1930d 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 537d 537d 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 668d 779d 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 123s! [swapper/1:0]
Modules linked in:
CPU: 1 PID: 0 Comm: swapper/1 Tainted: G        W         5.10.188-syzkaller-00574-gd96fc5f29172 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023
RIP: 0010:native_restore_fl arch/x86/include/asm/irqflags.h:41 [inline]
RIP: 0010:arch_local_irq_restore arch/x86/include/asm/irqflags.h:84 [inline]
RIP: 0010:kvm_wait+0xfc/0x150 arch/x86/kernel/kvm.c:926
Code: 38 f0 75 26 41 f7 c7 00 02 00 00 75 0f 0f 1f 44 00 00 0f 00 2d 85 46 d5 03 f4 eb 0e 0f 1f 44 00 00 0f 00 2d 76 46 d5 03 fb f4 <4c> 89 7c 24 18 ff 74 24 18 9d 48 c7 44 24 20 0e 36 e0 45 49 c7 04
RSP: 0018:ffffc90000170040 EFLAGS: 00000246
RAX: 0000000000000001 RBX: 1ffff9200002e00c RCX: 1ffffffff0cd8ddf
RDX: 0000000000000001 RSI: 0000000000000001 RDI: ffffc90000170080
RBP: ffffc900001700f0 R08: dffffc0000000000 R09: ffffed103ee2ae53
R10: 0000000000000000 R11: dffffc0000000001 R12: dffffc0000000000
R13: ffff8881f7157294 R14: 0000000000000001 R15: 0000000000000246
FS:  0000000000000000(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffdfcdbfb18 CR3: 0000000151161000 CR4: 00000000003506a0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 pv_wait arch/x86/include/asm/paravirt.h:564 [inline]
 pv_wait_node kernel/locking/qspinlock_paravirt.h:325 [inline]
 __pv_queued_spin_lock_slowpath+0x407/0xc70 kernel/locking/qspinlock.c:473
 pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:554 [inline]
 queued_spin_lock_slowpath arch/x86/include/asm/qspinlock.h:51 [inline]
 queued_spin_lock include/asm-generic/qspinlock.h:85 [inline]
 do_raw_spin_lock include/linux/spinlock.h:183 [inline]
 __raw_spin_lock include/linux/spinlock_api_smp.h:143 [inline]
 _raw_spin_lock+0x139/0x1b0 kernel/locking/spinlock.c:151
 spin_lock include/linux/spinlock.h:354 [inline]
 __dev_xmit_skb net/core/dev.c:3808 [inline]
 __dev_queue_xmit+0xbc0/0x28e0 net/core/dev.c:4147
 dev_queue_xmit+0x17/0x20 net/core/dev.c:4215
 neigh_hh_output include/net/neighbour.h:501 [inline]
 neigh_output include/net/neighbour.h:515 [inline]
 ip6_finish_output2+0xeec/0x1850 net/ipv6/ip6_output.c:145
 __ip6_finish_output+0x658/0x820 net/ipv6/ip6_output.c:210
 ip6_finish_output+0x34/0x1e0 net/ipv6/ip6_output.c:220
 NF_HOOK_COND include/linux/netfilter.h:288 [inline]
 ip6_output+0x1f7/0x4d0 net/ipv6/ip6_output.c:243
 dst_output include/net/dst.h:437 [inline]
 ip6_local_out+0x1ff/0x480 net/ipv6/output_core.c:161
 ip6_send_skb net/ipv6/ip6_output.c:1949 [inline]
 ip6_push_pending_frames+0x116/0x240 net/ipv6/ip6_output.c:1969
 icmpv6_push_pending_frames+0x2b8/0x450 net/ipv6/icmp.c:310
 icmp6_send+0x1527/0x1e00 net/ipv6/icmp.c:629
 __icmpv6_send include/linux/icmpv6.h:28 [inline]
 icmpv6_send include/linux/icmpv6.h:49 [inline]
 ip6_link_failure+0x36/0x190 net/ipv6/route.c:2662
 dst_link_failure include/net/dst.h:420 [inline]
 ndisc_error_report+0x9a/0xc0 net/ipv6/ndisc.c:712
 neigh_invalidate+0x243/0x470 net/core/neighbour.c:995
 neigh_timer_handler+0x778/0xe70 net/core/neighbour.c:1082
 call_timer_fn+0x3b/0x2d0 kernel/time/timer.c:1420
 expire_timers kernel/time/timer.c:1465 [inline]
 __run_timers+0x72a/0xa10 kernel/time/timer.c:1759
 run_timer_softirq+0x69/0xf0 kernel/time/timer.c:1772
 __do_softirq+0x268/0x5bb kernel/softirq.c:309
 asm_call_irq_on_stack+0xf/0x20
 </IRQ>
 __run_on_irqstack arch/x86/include/asm/irq_stack.h:26 [inline]
 run_on_irqstack_cond arch/x86/include/asm/irq_stack.h:77 [inline]
 do_softirq_own_stack+0x60/0x80 arch/x86/kernel/irq_64.c:77
 invoke_softirq kernel/softirq.c:405 [inline]
 __irq_exit_rcu+0x128/0x150 kernel/softirq.c:435
 irq_exit_rcu+0x9/0x10 kernel/softirq.c:447
 sysvec_apic_timer_interrupt+0xbf/0xe0 arch/x86/kernel/apic/apic.c:1094
 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:635
RIP: 0010:native_irq_disable arch/x86/include/asm/irqflags.h:49 [inline]
RIP: 0010:arch_local_irq_disable arch/x86/include/asm/irqflags.h:89 [inline]
RIP: 0010:acpi_safe_halt drivers/acpi/processor_idle.c:114 [inline]
RIP: 0010:acpi_idle_do_entry drivers/acpi/processor_idle.c:575 [inline]
RIP: 0010:acpi_idle_enter+0x416/0x760 drivers/acpi/processor_idle.c:710
Code: 89 de 48 83 e6 08 31 ff e8 47 39 bb fc 48 83 e3 08 0f 85 b0 00 00 00 0f 1f 44 00 00 e8 f3 34 bb fc 0f 00 2d 8c a2 b6 00 fb f4 <fa> e9 e1 00 00 00 49 83 c7 04 4c 89 f8 48 c1 e8 03 42 0f b6 04 30
RSP: 0018:ffffc90000107c30 EFLAGS: 000002d3
RAX: ffffffff84af5a8d RBX: 0000000000000000 RCX: ffff8881002913c0
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc90000107c70 R08: ffffffff84af5a79 R09: ffffed1020052279
R10: 0000000000000000 R11: dffffc0000000001 R12: 0000000000000001
R13: ffff888101faa004 R14: dffffc0000000000 R15: ffff8881061fb064
 cpuidle_enter_state+0x5e1/0x1550 drivers/cpuidle/cpuidle.c:249
 cpuidle_enter+0x5f/0xa0 drivers/cpuidle/cpuidle.c:364
 call_cpuidle kernel/sched/idle.c:160 [inline]
 cpuidle_idle_call kernel/sched/idle.c:241 [inline]
 do_idle+0x364/0x5c0 kernel/sched/idle.c:302
 cpu_startup_entry+0x18/0x20 kernel/sched/idle.c:398
 start_secondary+0x2e9/0x3a0 arch/x86/kernel/smpboot.c:276
 secondary_startup_64_no_verify+0xb1/0xbb
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 26535 Comm: syz-executor.2 Tainted: G        W         5.10.188-syzkaller-00574-gd96fc5f29172 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023
RIP: 0010:native_restore_fl arch/x86/include/asm/irqflags.h:41 [inline]
RIP: 0010:arch_local_irq_restore arch/x86/include/asm/irqflags.h:84 [inline]
RIP: 0010:kvm_wait+0xfc/0x150 arch/x86/kernel/kvm.c:926
Code: 38 f0 75 26 41 f7 c7 00 02 00 00 75 0f 0f 1f 44 00 00 0f 00 2d 85 46 d5 03 f4 eb 0e 0f 1f 44 00 00 0f 00 2d 76 46 d5 03 fb f4 <4c> 89 7c 24 18 ff 74 24 18 9d 48 c7 44 24 20 0e 36 e0 45 49 c7 04
RSP: 0018:ffffc900017feb00 EFLAGS: 00000246
RAX: 0000000000000003 RBX: 1ffff920002ffd64 RCX: ffffffff8150aa64
RDX: 0000000000000001 RSI: 0000000000000003 RDI: ffffc900017feb40
RBP: ffffc900017febb0 R08: dffffc0000000000 R09: fffffbfff0d9e09e
R10: 0000000000000000 R11: dffffc0000000001 R12: dffffc0000000000
R13: ffffffff86cf04ec R14: 0000000000000003 R15: 0000000000000246
FS:  00007f3a498f46c0(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b33122000 CR3: 0000000160de9000 CR4: 00000000003506b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
 pv_wait arch/x86/include/asm/paravirt.h:564 [inline]
 pv_wait_head_or_lock kernel/locking/qspinlock_paravirt.h:470 [inline]
 __pv_queued_spin_lock_slowpath+0x72f/0xc70 kernel/locking/qspinlock.c:508
 pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:554 [inline]
 queued_spin_lock_slowpath arch/x86/include/asm/qspinlock.h:51 [inline]
 queued_spin_lock include/asm-generic/qspinlock.h:85 [inline]
 do_raw_spin_lock include/linux/spinlock.h:183 [inline]
 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:136 [inline]
 _raw_spin_lock_bh+0x139/0x1b0 kernel/locking/spinlock.c:175
 spin_lock_bh include/linux/spinlock.h:359 [inline]
 get_dist_table+0x207/0x2e0 net/sched/sch_netem.c:798
 netem_change+0x974/0x1fb0 net/sched/sch_netem.c:988
 netem_init+0x5b/0xb0 net/sched/sch_netem.c:1075
 qdisc_create+0x879/0x12d0 net/sched/sch_api.c:1264
 tc_modify_qdisc+0x8a4/0x13f0
 rtnetlink_rcv_msg+0x955/0xc50 net/core/rtnetlink.c:5577
 netlink_rcv_skb+0x1cf/0x410 net/netlink/af_netlink.c:2497
 rtnetlink_rcv+0x1c/0x20 net/core/rtnetlink.c:5595
 netlink_unicast_kernel net/netlink/af_netlink.c:1322 [inline]
 netlink_unicast+0x8df/0xac0 net/netlink/af_netlink.c:1348
 netlink_sendmsg+0xa46/0xd00 net/netlink/af_netlink.c:1916
 sock_sendmsg_nosec net/socket.c:652 [inline]
 sock_sendmsg net/socket.c:672 [inline]
 ____sys_sendmsg+0x59e/0x8f0 net/socket.c:2357
 ___sys_sendmsg+0x252/0x2e0 net/socket.c:2411
 __sys_sendmsg net/socket.c:2440 [inline]
 __do_sys_sendmsg net/socket.c:2449 [inline]
 __se_sys_sendmsg+0x1b1/0x280 net/socket.c:2447
 __x64_sys_sendmsg+0x7b/0x90 net/socket.c:2447
 do_syscall_64+0x34/0x70
 entry_SYSCALL_64_after_hwframe+0x61/0xc6
RIP: 0033:0x7f3a4ab71ae9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 00 00 90 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 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f3a498f40c8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f3a4ac90f80 RCX: 00007f3a4ab71ae9
RDX: 0000000000000000 RSI: 00000000200001c0 RDI: 0000000000000006
RBP: 00007f3a4abbd47a R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000000b R14: 00007f3a4ac90f80 R15: 00007ffe1539d1f8

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2023/08/24 05:37 android13-5.10-lts d96fc5f29172 4d7ae7ab .config console log report info ci2-android-5-10 BUG: soft lockup in neigh_timer_handler
2023/08/16 01:19 android13-5.10-lts 8a427269c016 39990d51 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 BUG: soft lockup in neigh_timer_handler
* Struck through repros no longer work on HEAD.