INFO: rcu detected stall in NF

Kernel	Title	Rank 🛈	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
upstream	INFO: rcu detected stall in NF_HOOK netfilter usb	1	C	error		13	727d	741d	0/29	closed as dup on 2024/06/20 17:29
linux-5.15	INFO: rcu detected stall in NF_HOOK	1				1	846d	846d	0/3	auto-obsoleted due to no activity on 2024/06/15 14:02
linux-6.6	INFO: rcu detected stall in NF_HOOK origin:upstream	1	C		error	13	9h03m	227d	0/2	upstream: reported C repro on 2025/11/16 12:13
linux-5.15	INFO: rcu detected stall in NF_HOOK (3)	1				2	526d	545d	0/3	auto-obsoleted due to no activity on 2025/05/01 22:51
linux-6.1	INFO: rcu detected stall in NF_HOOK origin:lts-only	1	syz		unreliable	30	4d01h	757d	0/3	upstream: reported syz repro on 2024/06/04 14:31
upstream	INFO: rcu detected stall in NF_HOOK (2) prio:normal netfilter lsm	1	C	inconclusive	error	138	3h59m	629d	0/29	upstream: reported C repro on 2024/10/10 12:45
linux-5.15	INFO: rcu detected stall in NF_HOOK (2)	1				1	729d	729d	0/3	auto-obsoleted due to no activity on 2024/10/11 06:09
android-54	BUG: soft lockup in NF_HOOK	1				1	749d	749d	0/2	auto-obsoleted due to no activity on 2024/09/10 19:37

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: (detected by 1, t=10502 jiffies, g=55873, q=1626) rcu: All QSes seen, last rcu_preempt kthread activity 10480 (4295075038-4295064558), jiffies_till_next_fqs=1, root ->qsmask 0x0 rcu: rcu_preempt kthread starved for 10480 jiffies! g55873 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1 rcu: Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior. rcu: RCU grace-period kthread stack dump: task:rcu_preempt state:R running task stack:27536 pid: 15 ppid: 2 flags:0x00004000 Call Trace: <TASK> context_switch kernel/sched/core.c:5049 [inline] __schedule+0x11c3/0x4350 kernel/sched/core.c:6395 schedule+0x11b/0x1e0 kernel/sched/core.c:6478 schedule_timeout+0x184/0x2d0 kernel/time/timer.c:2117 rcu_gp_fqs_loop+0x2be/0x11f0 kernel/rcu/tree.c:1972 rcu_gp_kthread+0x9a/0x370 kernel/rcu/tree.c:2145 kthread+0x42e/0x520 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 </TASK> rcu: Stack dump where RCU GP kthread last ran: NMI backtrace for cpu 1 CPU: 1 PID: 10296 Comm: syz.5.506 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 Call Trace: <IRQ> dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106 nmi_cpu_backtrace+0x3a2/0x3d0 lib/nmi_backtrace.c:111 nmi_trigger_cpumask_backtrace+0x163/0x280 lib/nmi_backtrace.c:62 trigger_single_cpu_backtrace include/linux/nmi.h:166 [inline] rcu_check_gp_kthread_starvation+0x1cd/0x250 kernel/rcu/tree_stall.h:487 print_other_cpu_stall+0x1110/0x1270 kernel/rcu/tree_stall.h:592 check_cpu_stall kernel/rcu/tree_stall.h:745 [inline] rcu_pending kernel/rcu/tree.c:3936 [inline] rcu_sched_clock_irq+0x845/0x1120 kernel/rcu/tree.c:2619 update_process_times+0x193/0x200 kernel/time/timer.c:2021 tick_sched_handle kernel/time/tick-sched.c:254 [inline] tick_sched_timer+0x37d/0x560 kernel/time/tick-sched.c:1473 __run_hrtimer kernel/time/hrtimer.c:1685 [inline] __hrtimer_run_queues+0x4b0/0xb60 kernel/time/hrtimer.c:1749 hrtimer_interrupt+0x397/0x8b0 kernel/time/hrtimer.c:1811 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1097 [inline] __sysvec_apic_timer_interrupt+0x137/0x4a0 arch/x86/kernel/apic/apic.c:1114 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline] sysvec_apic_timer_interrupt+0x4d/0xc0 arch/x86/kernel/apic/apic.c:1108 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676 RIP: 0010:__sanitizer_cov_trace_const_cmp4+0x0/0x80 kernel/kcov.c:294 Code: 28 4d 39 ca 77 22 89 ff 89 f6 4a c7 44 02 08 03 00 00 00 4a 89 7c 02 10 4a 89 74 02 18 4a 89 44 02 20 48 ff c1 48 89 0a c3 90 <48> 8b 04 24 65 48 8b 0d b4 79 89 7e 65 8b 15 b5 79 89 7e 81 e2 00 RSP: 0018:ffffc90000dd0678 EFLAGS: 00000246 RAX: 0000000000000001 RBX: ffffc90000dd0a20 RCX: 02349a42ed97fb00 RDX: 0000000000000100 RSI: 0000000000000001 RDI: 0000000000000001 RBP: 0000000000000001 R08: ffff8880490d999f R09: 1ffff1100921b333 R10: dffffc0000000000 R11: ffffed100921b334 R12: 0000000000000000 R13: 0000000000000000 R14: ffff8880490d98c0 R15: 0000000000000000 nf_conntrack_handle_icmp+0xe0/0x180 net/netfilter/nf_conntrack_core.c:1859 nf_conntrack_in+0x13a4/0x17b0 net/netfilter/nf_conntrack_core.c:1949 nf_hook_entry_hookfn include/linux/netfilter.h:142 [inline] nf_hook_slow+0xb9/0x200 net/netfilter/core.c:584 nf_hook include/linux/netfilter.h:257 [inline] NF_HOOK+0x1f2/0x390 include/linux/netfilter.h:300 __netif_receive_skb_one_core net/core/dev.c:5551 [inline] __netif_receive_skb+0xcc/0x290 net/core/dev.c:5665 process_backlog+0x366/0x770 net/core/dev.c:6542 __napi_poll+0xbb/0x430 net/core/dev.c:7101 napi_poll net/core/dev.c:7168 [inline] net_rx_action+0x522/0xa80 net/core/dev.c:7258 handle_softirqs+0x336/0x830 kernel/softirq.c:576 __do_softirq kernel/softirq.c:610 [inline] invoke_softirq kernel/softirq.c:450 [inline] __irq_exit_rcu+0x13b/0x230 kernel/softirq.c:659 irq_exit_rcu+0x5/0x20 kernel/softirq.c:671 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline] sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1108 </IRQ> <TASK> asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676 RIP: 0010:preempt_schedule_irq+0xb6/0x160 kernel/sched/core.c:6799 Code: 00 00 43 c6 44 37 04 f8 74 0b 0f 0b 48 f7 03 08 00 00 00 74 7f bf 01 00 00 00 e8 15 2a 90 f7 e8 70 fd bc f7 fb bf 01 00 00 00 <e8> d5 b5 ff ff 43 c6 44 37 08 00 48 c7 44 24 40 00 00 00 00 9c 8f RSP: 0018:ffffc90002fffda0 EFLAGS: 00000286 RAX: 02349a42ed97fb00 RBX: 0000000000000000 RCX: 02349a42ed97fb00 RDX: dffffc0000000000 RSI: ffffffff8a2b2be0 RDI: 0000000000000001 RBP: ffffc90002fffe40 R08: ffff8880b913b30b R09: 1ffff11017227661 R10: dffffc0000000000 R11: ffffed1017227662 R12: 0000000000000000 R13: 0000000000000000 R14: dffffc0000000000 R15: 1ffff920005fffb4 irqentry_exit+0x63/0x70 kernel/entry/common.c:432 asm_sysvec_apic_timer_interrupt+0x16/0x20 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+0x2a/0x70 kernel/entry/common.c:114 Code: 41 56 53 48 89 f3 49 89 fe 48 8b 7c 24 10 e8 3d f6 ff ff eb 31 eb 35 e8 d4 3a c5 f7 e8 cf 38 c5 f7 fb 65 48 8b 05 06 8e 48 76 <48> 8b 70 08 40 f6 c6 3f 74 0b 4c 89 f7 5b 41 5e e9 f1 3b ad f7 48 RSP: 0018:ffffc90002ffff08 EFLAGS: 00000286 RAX: ffff888026909dc0 RBX: 00000000000000ca RCX: 02349a42ed97fb00 RDX: dffffc0000000000 RSI: ffffffff8a2b2be0 RDI: ffffffff8a79c980 RBP: ffffc90002ffff48 R08: ffffffff8d89e06f R09: 1ffffffff1b13c0d R10: dffffc0000000000 R11: fffffbfff1b13c0e R12: 0000000000000000 R13: 0000000000000000 R14: ffffc90002ffff58 R15: 0000000000000000 do_syscall_64+0x24/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7fb976de3e59 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:00007fb97503d0e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: ffffffffffffffda RBX: 00007fb97705cfa8 RCX: 00007fb976de3e59 RDX: 00000000000f4240 RSI: 0000000000000081 RDI: 00007fb97705cfac RBP: 00007fb97705cfa0 R08: 0018056ce144e824 R09: 0000000000000000 R10: ffffffffffffffff R11: 0000000000000246 R12: 0000000000000000 R13: 00007fb97705d038 R14: 00007ffd94ab02a0 R15: 00007ffd94ab0388 </TASK>

Crashes (2):
Time	Kernel	Commit	Syzkaller	Config	Log	Report	Syz repro	C repro	VM info	Assets (help?)	Manager	Title
2026/07/01 01:34	linux-5.15.y	eceeec79dbc6	00e8b0fd	.config	console log	report			info	[disk image] [vmlinux] [kernel image]	ci2-linux-5-15-kasan-perf	INFO: rcu detected stall in NF_HOOK
2026/06/30 08:20	linux-5.15.y	eceeec79dbc6	fff8d0a0	.config	console log	report			info	[disk image] [vmlinux] [kernel image]	ci2-linux-5-15-kasan-perf	INFO: rcu detected stall in NF_HOOK

Crashes (2):

Assets (help?)