INFO: rcu detected stall in irqentry_exit (2)

Status: upstream: reported on 2025/09/16 14:07
Reported-by: syzbot+052866219c84faa6fcbe@syzkaller.appspotmail.com
First crash: 339d, last: 2d14h
▶ ▼ 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 734d 734d 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 syz, C inconclusive 28 4d11h 361d 0/2 upstream: reported C repro on 2025/08/25 11:36
linux-6.1 INFO: rcu detected stall in irqentry_exit (2) origin:lts-only 1 syz error 6 2d09h 283d 0/3 upstream: reported syz repro on 2025/11/10 20:44
linux-5.15 INFO: rcu detected stall in irqentry_exit 1 1 801d 801d 0/3 auto-obsoleted due to no activity on 2024/09/18 22:14
upstream INFO: rcu detected stall in irqentry_exit (2) kernel 1 syz, C 1 317d 317d 0/29 closed as invalid on 2026/01/13 17:54
upstream INFO: rcu detected stall in irqentry_exit kernel 1 syz inconclusive inconclusive 2 610d 606d 0/29 auto-obsoleted due to no activity on 2025/03/29 05:27

Sample crash report:
rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	0-...!: (1 GPs behind) idle=a81/1/0x4000000000000000 softirq=65724/65725 fqs=557 
	(t=10502 jiffies g=95777 q=210)
rcu: rcu_preempt kthread starved for 9389 jiffies! g95777 f0x0 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:27872 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:
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1 skipped: idling at native_safe_halt arch/x86/include/asm/irqflags.h:51 [inline]
NMI backtrace for cpu 1 skipped: idling at arch_safe_halt arch/x86/include/asm/irqflags.h:89 [inline]
NMI backtrace for cpu 1 skipped: idling at default_idle+0xb/0x10 arch/x86/kernel/process.c:729
NMI backtrace for cpu 0
CPU: 0 PID: 17265 Comm: syz.2.3147 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
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_dump_cpu_stacks+0x22d/0x380 kernel/rcu/tree_stall.h:349
 print_cpu_stall+0x31f/0x5f0 kernel/rcu/tree_stall.h:633
 check_cpu_stall kernel/rcu/tree_stall.h:727 [inline]
 rcu_pending kernel/rcu/tree.c:3936 [inline]
 rcu_sched_clock_irq+0x6ec/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+0x9b/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:finish_lock_switch+0x12f/0x290 kernel/sched/core.c:4804
Code: 83 c7 18 be ff ff ff ff e8 6e cb 6b 08 85 c0 74 46 4d 85 ff 75 62 e9 06 01 00 00 48 89 df e8 98 3a 75 08 e8 43 d7 2a 00 fb 5b <41> 5c 41 5d 41 5e 41 5f 5d c3 48 89 df e8 2f 0e fe ff 43 80 3c 2c
RSP: 0018:ffffc90002ecfb38 EFLAGS: 00000286
RAX: a03ce4ffa0fc4800 RBX: ffff88804fe85940 RCX: a03ce4ffa0fc4800
RDX: dffffc0000000000 RSI: ffffffff8a2b2be0 RDI: ffffffff8a7a4200
RBP: 1ffff11017207613 R08: ffff8880b903a343 R09: 1ffff11017207468
R10: dffffc0000000000 R11: ffffed1017207469 R12: ffff8880b903b088
R13: dffffc0000000000 R14: ffff8880b903ae08 R15: 0000000000000000
 finish_task_switch+0x12f/0x650 kernel/sched/core.c:4921
 context_switch kernel/sched/core.c:5052 [inline]
 __schedule+0x11cb/0x4350 kernel/sched/core.c:6395
 preempt_schedule_irq+0xbb/0x160 kernel/sched/core.c:6799
 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 24 05 bf f7 e8 1f 03 bf f7 fb 65 48 8b 05 f6 4f 42 76 <48> 8b 70 08 40 f6 c6 3f 74 0b 4c 89 f7 5b 41 5e e9 a1 00 a7 f7 48
RSP: 0018:ffffc90002ecff08 EFLAGS: 00000286
RAX: ffff888079cc0000 RBX: 0000000000000027 RCX: a03ce4ffa0fc4800
RDX: dffffc0000000000 RSI: ffffffff8a2b2be0 RDI: ffffffff8a7a4200
RBP: ffffc90002ecff48 R08: ffffffff8d8b0def R09: 1ffffffff1b161bd
R10: dffffc0000000000 R11: fffffbfff1b161be R12: 0000000000000000
R13: 0000000000000000 R14: ffffc90002ecff58 R15: 0000000000000000
 do_syscall_64+0x24/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f89ee864e57
Code: 8d 3d c0 9e 0b 00 e8 58 1d fa ff e8 a3 87 00 00 0f 1f 00 b8 68 00 00 00 0f 05 c3 0f 1f 84 00 00 00 00 00 b8 27 00 00 00 0f 05 <c3> 0f 1f 84 00 00 00 00 00 b8 6e 00 00 00 0f 05 c3 0f 1f 84 00 00
RSP: 002b:00007ffe440dbf08 EFLAGS: 00000202 ORIG_RAX: 0000000000000027
RAX: ffffffffffffffda RBX: 00007ffe440dc070 RCX: 00007f89ee864e57
RDX: 00007ffe440dbf40 RSI: 00007ffe440dc070 RDI: 0000000000000021
RBP: 0000000000000000 R08: 000000000000000f R09: 0000000000000000
R10: 00007f89eeaf2fa0 R11: 0000000000000202 R12: 0000000000000000
R13: 00007f89eeaf2fac R14: 00007f89eeaf2fa8 R15: 00007f89eeaf2fa0
 </TASK>

Crashes (17):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/08/19 01:38 linux-5.15.y aabd761612db 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in irqentry_exit
2026/08/12 22:46 linux-5.15.y aabd761612db 359b2492 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in irqentry_exit
2026/08/10 21:57 linux-5.15.y aabd761612db 508909ea .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in irqentry_exit
2026/08/02 02:41 linux-5.15.y 6e2fd6534337 e611ffe1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in irqentry_exit
2026/07/30 06:45 linux-5.15.y 674f684f7c61 6ef5c1e2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in irqentry_exit
2026/07/20 08:14 linux-5.15.y c86c4726e7f0 72524a66 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in irqentry_exit
2026/07/16 22:48 linux-5.15.y c86c4726e7f0 71b49442 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in irqentry_exit
2026/06/04 15:16 linux-5.15.y dc027a595035 197909be .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in irqentry_exit
2026/05/28 08:16 linux-5.15.y 241d66fa280c 4c36e7e5 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in irqentry_exit
2026/05/12 16:57 linux-5.15.y de8dfb3f0278 07aeade5 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in irqentry_exit
2026/05/04 05:39 linux-5.15.y ef251c45f1cd a0d91488 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in irqentry_exit
2026/03/05 05:55 linux-5.15.y 91d48252ad4b a9fe5c9e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in irqentry_exit
2026/02/12 07:57 linux-5.15.y e45d5d41c134 76a109e2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in irqentry_exit
2025/12/07 10:23 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in irqentry_exit
2025/11/15 09:16 linux-5.15.y cc5ec8769306 f7988ea4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in irqentry_exit
2025/10/13 18:16 linux-5.15.y 29e53a5b1c4f b6605ba8 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in irqentry_exit
2025/09/16 14:07 linux-5.15.y 43bb85222e53 e2beed91 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in irqentry_exit
* Struck through repros no longer work on HEAD.