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INFO: rcu detected stall in irqentry_exit (2)

Status: closed as invalid on 2026/01/13 17:54
Subsystems: kernel
[Documentation on labels]
First crash: 113d, last: 113d
Similar bugs (6)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.1 INFO: rcu detected stall in irqentry_exit 1 1 530d 530d 0/3 auto-obsoleted due to no activity on 2024/11/25 13:22
linux-6.6 INFO: rcu detected stall in irqentry_exit origin:lts-only 1 C inconclusive 12 3d17h 157d 0/2 upstream: reported C repro on 2025/08/25 11:36
linux-5.15 INFO: rcu detected stall in irqentry_exit (2) 1 4 53d 135d 0/3 upstream: reported on 2025/09/16 14:07
linux-6.1 INFO: rcu detected stall in irqentry_exit (2) origin:lts-only 1 syz error 1 80d 80d 0/3 upstream: reported syz repro on 2025/11/10 20:44
linux-5.15 INFO: rcu detected stall in irqentry_exit 1 1 598d 598d 0/3 auto-obsoleted due to no activity on 2024/09/18 22:14
upstream INFO: rcu detected stall in irqentry_exit kernel 1 syz inconclusive inconclusive 2 406d 402d 0/29 auto-obsoleted due to no activity on 2025/03/29 05:27
Last patch testing requests (2)
Created Duration User Patch Repo Result
2025/12/31 14:07 17m retest repro upstream report log
2025/10/22 13:38 15m retest repro upstream report log

Sample crash report:
hrtimer: interrupt took 41958 ns
rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	0-...!: (10500 ticks this GP) idle=62bc/1/0x4000000000000000 softirq=33186/33186 fqs=0
rcu: 	(t=10500 jiffies g=25161 q=210 ncpus=1)
rcu: rcu_preempt kthread starved for 10500 jiffies! g25161 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0
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:28456 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5325 [inline]
 __schedule+0x1798/0x4cc0 kernel/sched/core.c:6929
 __schedule_loop kernel/sched/core.c:7011 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:7026
 schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99
 rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2083
 rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2285
 kthread+0x711/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
CPU: 0 UID: 0 PID: 5501 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
RIP: 0010:___neigh_lookup_noref include/net/neighbour.h:315 [inline]
RIP: 0010:__ipv6_neigh_lookup_noref+0x21c/0x710 include/net/ndisc.h:359
Code: 89 fb 48 c1 e3 03 48 03 5d 00 48 89 d8 48 c1 e8 03 49 bf 00 00 00 00 00 fc ff df 42 80 3c 38 00 74 08 48 89 df e8 d4 ed 2a f8 <48> 8b 2b 48 85 ed 4c 8b 74 24 30 0f 84 ff 02 00 00 4c 89 6c 24 38
RSP: 0018:ffffc90000007668 EFLAGS: 00010246
RAX: 1ffff110022f0e7d RBX: ffff8880117873e8 RCX: dffffc0000000000
RDX: 0000000000000100 RSI: 0000000000000018 RDI: 0000000000000020
RBP: ffff8880119e5980 R08: ffff88804356aeb7 R09: 1ffff110086ad5d6
R10: dffffc0000000000 R11: ffffed10086ad5d7 R12: 0000000000000000
R13: ffff888035ea6498 R14: ffff8880119e5988 R15: dffffc0000000000
FS:  00007f0c390ca6c0(0000) GS:ffff88808d306000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000557ea691d138 CR3: 0000000058ac2000 CR4: 0000000000352ef0
Call Trace:
 <IRQ>
 ip6_finish_output2+0x820/0x1480 net/ipv6/ip6_output.c:124
 __ip6_finish_output net/ipv6/ip6_output.c:-1 [inline]
 ip6_finish_output+0x234/0x7d0 net/ipv6/ip6_output.c:220
 NF_HOOK_COND include/linux/netfilter.h:307 [inline]
 ip6_output+0x340/0x550 net/ipv6/ip6_output.c:247
 NF_HOOK include/linux/netfilter.h:318 [inline]
 ndisc_send_skb+0xbce/0x1510 net/ipv6/ndisc.c:512
 addrconf_rs_timer+0x369/0x670 net/ipv6/addrconf.c:4037
 call_timer_fn+0x17e/0x5f0 kernel/time/timer.c:1747
 expire_timers kernel/time/timer.c:1798 [inline]
 __run_timers kernel/time/timer.c:2372 [inline]
 __run_timer_base+0x61a/0x860 kernel/time/timer.c:2384
 run_timer_base kernel/time/timer.c:2393 [inline]
 run_timer_softirq+0xb7/0x180 kernel/time/timer.c:2403
 handle_softirqs+0x283/0x870 kernel/softirq.c:622
 __do_softirq kernel/softirq.c:656 [inline]
 invoke_softirq kernel/softirq.c:496 [inline]
 __irq_exit_rcu+0xca/0x1f0 kernel/softirq.c:723
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:739
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1052 [inline]
 sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1052
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:preempt_schedule_irq+0xb0/0x150 kernel/sched/core.c:7256
Code: 24 20 f6 44 24 21 02 74 0c 90 0f 0b 48 f7 03 10 00 00 00 74 64 bf 01 00 00 00 e8 9b 14 41 f6 e8 a6 e7 78 f6 fb bf 01 00 00 00 <e8> 5b ab ff ff 48 c7 44 24 40 00 00 00 00 9c 8f 44 24 40 8b 44 24
RSP: 0018:ffffc9000cbdfbc0 EFLAGS: 00000282
RAX: 644afc1ec71bca00 RBX: 0000000000000000 RCX: 644afc1ec71bca00
RDX: 0000000000000000 RSI: ffffffff8d7eb538 RDI: 0000000000000001
RBP: ffffc9000cbdfc60 R08: ffffffff8f9e2f77 R09: 1ffffffff1f3c5ee
R10: dffffc0000000000 R11: fffffbfff1f3c5ef R12: 0000000000000000
R13: 0000000000000000 R14: dffffc0000000000 R15: 1ffff9200197bf78
 irqentry_exit+0x6f/0x90 kernel/entry/common.c:211
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:task_mm_cid_work+0x116/0x760 kernel/sched/core.c:10762
Code: 4d 06 00 00 41 f6 06 04 0f 85 f4 05 00 00 48 81 c3 98 05 00 00 48 89 d8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df 80 3c 08 00 <74> 08 48 89 df e8 50 81 95 00 48 8b 03 48 89 44 24 08 48 85 c0 0f
RSP: 0018:ffffc9000cbdfd20 EFLAGS: 00000246
RAX: 1ffff110038d80b3 RBX: ffff88801c6c0598 RCX: dffffc0000000000
RDX: 1ffff9200197bfac RSI: ffffffff8d7eb538 RDI: ffff88801c6c15d8
RBP: ffffc9000cbdfdf0 R08: ffffffff8f9e2f77 R09: 1ffffffff1f3c5ee
R10: dffffc0000000000 R11: ffffffff81914970 R12: dffffc0000000000
R13: ffff88801c6c15d8 R14: ffff88801c6c002c R15: 00000000ffffcf1b
 task_work_run+0x1d4/0x260 kernel/task_work.c:227
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 exit_to_user_mode_loop+0xe9/0x130 kernel/entry/common.c:43
 exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline]
 syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline]
 do_syscall_64+0x2bd/0xfa0 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f0c3818eec9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f0c390ca038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: 0000000000000000 RBX: 00007f0c383e5fa0 RCX: 00007f0c3818eec9
RDX: 00002000000006c0 RSI: 0000000000005452 RDI: 0000000000000003
RBP: 00007f0c38211f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f0c383e6038 R14: 00007f0c383e5fa0 R15: 00007ffcd8899658
 </TASK>

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/10/08 13:12 upstream 0d97f2067c16 7e2882b3 .config console log report syz / log C [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root INFO: rcu detected stall in irqentry_exit
* Struck through repros no longer work on HEAD.