BUG: soft lockup in ip_expire

Status: premoderation: reported on 2026/11/10 06:24
Reported-by: syzbot+fb952c43b8c93bd49688@syzkaller.appspotmail.com
First crash: 1d04h, last: 1d04h
▶ ▼ Similar bugs (6)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.6 INFO: rcu detected stall in ip_expire 1 5 4d06h 51d 0/2 upstream: reported on 2026/09/20 15:33
upstream BUG: soft lockup in ip_expire net 1 1 415d 415d 0/29 closed as invalid on 2025/11/14 20:35
linux-6.1 INFO: rcu detected stall in ip_expire (2) 1 1 157d 157d 0/3 auto-obsoleted due to no activity on 2026/09/15 02:40
linux-5.15 INFO: rcu detected stall in ip_expire (2) 1 2 36d 37d 0/3 upstream: reported on 2026/10/05 00:10
linux-6.1 INFO: rcu detected stall in ip_expire 1 1 780d 780d 0/3 auto-obsoleted due to no activity on 2024/12/30 13:44
linux-5.15 INFO: rcu detected stall in ip_expire 1 1 348d 348d 0/3 auto-obsoleted due to no activity on 2026/03/08 05:26

Sample crash report:
watchdog: BUG: soft lockup - CPU#0 stuck for 123s! [syz.4.14437:27158]
Modules linked in:
CPU: 0 PID: 27158 Comm: syz.4.14437 Tainted: G        W         syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/06/2026
RIP: 0010:net_hash_mix include/net/netns/hash.h:9 [inline]
RIP: 0010:inet_addr_hash net/ipv4/devinet.c:123 [inline]
RIP: 0010:inet_lookup_ifaddr_rcu+0x34/0x190 net/ipv4/devinet.c:183
Code: 41 54 53 89 f3 49 89 fe 49 bd 00 00 00 00 00 fc ff df e8 ef 05 83 fd 4d 8d be 40 01 00 00 4c 89 f8 48 c1 e8 03 42 0f b6 04 28 <84> c0 0f 85 35 01 00 00 41 8b 07 31 d8 69 c0 47 86 c8 61 c1 e8 18
RSP: 0018:ffffc90000007828 EFLAGS: 00000a02
RAX: 0000000000000000 RBX: 000000000c1414ac RCX: ffff88811e9a2800
RDX: 0000000000000102 RSI: 000000000c1414ac RDI: ffff888119112680
RBP: ffffc90000007850 R08: 0000000000000000 R09: ffff888102dc2000
R10: dffffc0000000000 R11: fffff52000000f96 R12: ffff88811a3dbc00
R13: dffffc0000000000 R14: ffff888119112680 R15: ffff8881191127c0
FS:  00007fe8818cd6c0(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c2e6aa1 CR3: 0000000127a94000 CR4: 00000000003506b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 fib_validate_source+0xd65/0x1360 net/ipv4/fib_frontend.c:439
 ip_mc_validate_source net/ipv4/route.c:1791 [inline]
 ip_route_input_mc net/ipv4/route.c:1809 [inline]
 ip_route_input_rcu+0xd8a/0x25a0 net/ipv4/route.c:2443
 ip_route_input_noref+0xd0/0x130 net/ipv4/route.c:2394
 ip_expire+0x35e/0x630 net/ipv4/ip_fragment.c:177
 call_timer_fn+0x38/0x290 kernel/time/timer.c:1450
 expire_timers kernel/time/timer.c:1495 [inline]
 __run_timers+0x637/0x9a0 kernel/time/timer.c:1789
 run_timer_softirq+0x6a/0xf0 kernel/time/timer.c:1802
 __do_softirq+0x255/0x563 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:1106
 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:635
RIP: 0010:queue_work_on+0xf5/0x140 kernel/workqueue.c:1550
Code: 31 24 00 eb 16 e8 5b 31 24 00 8b 7c 24 04 48 8b 74 24 08 48 89 da e8 5a 00 00 00 48 8b 44 24 10 48 89 44 24 18 ff 74 24 18 9d <48> c7 44 24 20 0e 36 e0 45 4b c7 44 35 00 00 00 00 00 65 48 8b 04
RSP: 0018:ffffc900010bf7a0 EFLAGS: 00000293
RAX: 0000000000000293 RBX: ffffffff864fce00 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000802 RDI: ffff88811e9a2800
RBP: ffffc900010bf850 R08: ffffffff86c383ef R09: 1ffffffff0d8707d
R10: dffffc0000000000 R11: fffffbfff0d8707e R12: 0000000000000000
R13: 1ffff92000217ef8 R14: dffffc0000000000 R15: ffff8881171e3a01
 queue_work include/linux/workqueue.h:515 [inline]
 schedule_work include/linux/workqueue.h:576 [inline]
 percpu_rwsem_async_destroy+0xe2/0xf0 kernel/locking/percpu-rwsem.c:302
 mmu_notifier_subscriptions_destroy include/linux/mmu_notifier.h:527 [inline]
 __mmdrop+0x13c/0x490 kernel/fork.c:728
 mmdrop include/linux/sched/mm.h:49 [inline]
 finish_task_switch+0x1e2/0x5a0 kernel/sched/core.c:3905
 context_switch kernel/sched/core.c:4051 [inline]
 __schedule+0xc0b/0x13e0 kernel/sched/core.c:4806
 preempt_schedule_common+0x9b/0xf0 kernel/sched/core.c:4965
 preempt_schedule+0xbc/0xd0 kernel/sched/core.c:4990
 preempt_schedule_thunk+0x16/0x18 arch/x86/entry/thunk_64.S:39
 smp_call_function_single+0x3f7/0x490 kernel/smp.c:519
 task_function_call kernel/events/core.c:116 [inline]
 perf_install_in_context+0x4c7/0x770 kernel/events/core.c:2969
 __do_sys_perf_event_open kernel/events/core.c:12286 [inline]
 __se_sys_perf_event_open+0x1246/0x1b40 kernel/events/core.c:11878
 __x64_sys_perf_event_open+0xbf/0xd0 kernel/events/core.c:11878
 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x61/0xcb
RIP: 0033:0x7fe882e7ef19
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:00007fe8818cd028 EFLAGS: 00000246 ORIG_RAX: 000000000000012a
RAX: ffffffffffffffda RBX: 00007fe8830fbfa0 RCX: 00007fe882e7ef19
RDX: ffffffffffffffff RSI: 0000000000000000 RDI: 0000200000001340
RBP: 00007fe882f0df6d R08: 0000000000000000 R09: 0000000000000000
R10: ffffffffffffffff R11: 0000000000000246 R12: 0000000000000000
R13: 00007fe8830fc038 R14: 00007fe8830fbfa0 R15: 00007ffc7b4ffbc8
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 678 Comm: kworker/u4:4 Tainted: G        W         syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/06/2026
Workqueue: events_unbound toggle_allocation_gate
RIP: 0010:csd_lock_wait kernel/smp.c:229 [inline]
RIP: 0010:smp_call_function_single+0x209/0x490 kernel/smp.c:517
Code: 48 44 89 f6 83 e6 01 31 ff e8 63 90 0a 00 41 83 e6 01 49 bc 00 00 00 00 00 fc ff df 75 0a e8 9e 8c 0a 00 e9 a4 00 00 00 f3 90 <f7> 44 24 48 01 00 00 00 0f 84 8f 00 00 00 e8 84 8c 0a 00 eb e9 e8
RSP: 0018:ffffc9000126f700 EFLAGS: 00000293
RAX: ffffffff815a2a3c RBX: 0000000000000000 RCX: ffff88811885bc00
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc9000126f7f0 R08: ffffffff86c383ef R09: 1ffffffff0d8707d
R10: dffffc0000000000 R11: fffffbfff0d8707e R12: dffffc0000000000
R13: 0000000000000001 R14: 0000000000000001 R15: 1ffff9200024dee4
FS:  0000000000000000(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ff351430000 CR3: 000000000640f000 CR4: 00000000003506a0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 smp_call_function_many_cond+0x8f5/0x9d0 kernel/smp.c:653
 smp_call_function_many kernel/smp.c:716 [inline]
 smp_call_function kernel/smp.c:738 [inline]
 on_each_cpu+0xab/0x180 kernel/smp.c:837
 text_poke_sync arch/x86/kernel/alternative.c:1568 [inline]
 text_poke_bp_batch+0x1cb/0x5f0 arch/x86/kernel/alternative.c:1768
 text_poke_flush arch/x86/kernel/alternative.c:1959 [inline]
 text_poke_finish+0x1a/0x30 arch/x86/kernel/alternative.c:1966
 arch_jump_label_transform_apply+0x15/0x30 arch/x86/kernel/jump_label.c:126
 __jump_label_update+0x38f/0x3b0 kernel/jump_label.c:459
 jump_label_update+0x34c/0x3e0 kernel/jump_label.c:825
 static_key_enable_cpuslocked+0x126/0x240 kernel/jump_label.c:177
 static_key_enable+0x1a/0x30 kernel/jump_label.c:190
 toggle_allocation_gate+0xba/0x440 mm/kfence/core.c:624
 process_one_work+0x6fd/0xbc0 kernel/workqueue.c:2301
 worker_thread+0xa8e/0x13c0 kernel/workqueue.c:2447
 kthread+0x324/0x3b0 kernel/kthread.c:313
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/11/10 06:23 android13-5.10-lts f61a392235e0 70ec0380 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10-perf BUG: soft lockup in ip_expire
* Struck through repros no longer work on HEAD.