syzbot

 sign-in | mailing list | source | docs
🐞 Open [851]
🐞 Fixed [87]
🐞 Invalid [1240]
⬇ Missing Backports [132]
≡ Crashes
Kernel Health Bugs/Month Bug Lifetimes Fuzzing
💬 Send us feedback

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: 175d, last: 6d03h
▶ ▼ 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 570d 570d 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 16 3d04h 197d 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 1 120d 120d 0/3 upstream: reported syz repro on 2025/11/10 20:44
linux-5.15 INFO: rcu detected stall in irqentry_exit 1 1 638d 638d 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 C 1 153d 153d 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 447d 443d 0/29 auto-obsoleted due to no activity on 2025/03/29 05:27

Sample crash report:
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	0-....: (11 ticks this GP) idle=baf/1/0x4000000000000002 softirq=78343/78343 fqs=5236 
	(detected by 1, t=10502 jiffies, g=110277, q=1816)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 26412 Comm: syz.9.6498 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:test_bit include/asm-generic/bitops/instrumented-non-atomic.h:134 [inline]
RIP: 0010:hlock_class kernel/locking/lockdep.c:197 [inline]
RIP: 0010:__lock_acquire+0x12cf/0x7d10 kernel/locking/lockdep.c:5009
Code: fc ff df 48 83 3b 00 0f 84 f0 49 00 00 48 8b 44 24 58 42 0f b6 04 00 84 c0 0f 85 b2 5a 00 00 41 8b 07 89 c3 81 e3 ff 1f 00 00 <c1> e8 03 25 f8 03 00 00 48 8d b8 c0 40 1d 90 be 08 00 00 00 e8 08
RSP: 0018:ffffc90000007000 EFLAGS: 00000002
RAX: 00000000000a2015 RBX: 0000000000000015 RCX: ffffffff815d15ce
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff901d40c0
RBP: ffffc90000007250 R08: dffffc0000000000 R09: 1ffffffff203a818
R10: dffffc0000000000 R11: fffffbfff203a819 R12: 00000000a8c0100a
R13: ffff888072fd5940 R14: 00000000fee1e9ca R15: ffff888072fd64a0
FS:  00007f2210cca6c0(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c369acf CR3: 000000002b93c000 CR4: 00000000003506f0
DR0: 0000200000000300 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 lock_acquire+0x19e/0x400 kernel/locking/lockdep.c:5623
 rcu_lock_acquire+0x2a/0x30 include/linux/rcupdate.h:313
 rcu_read_lock include/linux/rcupdate.h:740 [inline]
 __perf_event_output kernel/events/core.c:7800 [inline]
 perf_event_output_forward+0xbc/0x2e0 kernel/events/core.c:7822
 __perf_event_overflow+0x364/0x530 kernel/events/core.c:9515
 perf_tp_event+0x383/0xbf0 kernel/events/core.c:10047
 perf_trace_run_bpf_submit+0xf3/0x1c0 kernel/events/core.c:10021
 perf_trace_preemptirq_template+0x2aa/0x360 include/trace/events/preemptirq.h:14
 trace_irq_enable_rcuidle+0x108/0x180 include/trace/events/preemptirq.h:40
 trace_hardirqs_on+0x57/0x80 kernel/trace/trace_preemptirq.c:44
 asm_sysvec_irq_work+0x16/0x20 arch/x86/include/asm/idtentry.h:713
RIP: 0010:rcu_read_unlock_special+0x7f/0x4a0 kernel/rcu/tree_plugin.h:674
Code: eb 03 48 b8 f1 f1 f1 f1 f8 f2 f2 f2 4a 89 04 2b 42 c7 44 2b 08 f8 f3 f3 f3 65 44 8b 35 12 f2 9c 7e 41 f7 c6 00 00 f0 00 74 40 <48> c7 44 24 20 0e 36 e0 45 4a c7 04 2b 00 00 00 00 42 c7 44 2b 08
RSP: 0018:ffffc900000079e0 EFLAGS: 00000206
RAX: d30c55e2b6d4b100 RBX: 1ffff92000000f40 RCX: d30c55e2b6d4b100
RDX: dffffc0000000000 RSI: ffffffff8a2b2780 RDI: ffffffff8a79f980
RBP: ffffc90000007ac0 R08: ffffffff901d41bf R09: 1ffffffff203a837
R10: dffffc0000000000 R11: fffffbfff203a838 R12: ffffffff8c322f00
R13: dffffc0000000000 R14: 0000000000000246 R15: 0000000000000001
 __rcu_read_unlock+0x78/0xd0 kernel/rcu/tree_plugin.h:422
 rcu_read_unlock include/linux/rcupdate.h:772 [inline]
 hsr_announce+0x29a/0x310 net/hsr/hsr_device.c:410
 call_timer_fn+0x17b/0x540 kernel/time/timer.c:1648
 expire_timers kernel/time/timer.c:1699 [inline]
 __run_timers+0x53e/0x800 kernel/time/timer.c:1970
 run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1983
 handle_softirqs+0x339/0x830 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 85 ae 8d f7 e8 c0 9a ba f7 fb bf 01 00 00 00 <e8> 65 b5 ff ff 43 c6 44 37 08 00 48 c7 44 24 40 00 00 00 00 9c 8f
RSP: 0018:ffffc900025a7da0 EFLAGS: 00000286
RAX: d30c55e2b6d4b100 RBX: 0000000000000000 RCX: d30c55e2b6d4b100
RDX: dffffc0000000000 RSI: ffffffff8a2b2780 RDI: 0000000000000001
RBP: ffffc900025a7e40 R08: ffff8880b903b30b R09: 1ffff11017207661
R10: dffffc0000000000 R11: ffffed1017207662 R12: 0000000000000000
R13: 0000000000000000 R14: dffffc0000000000 R15: 1ffff920004b4fb4
 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 da c2 f7 e8 cf d8 c2 f7 fb 65 48 8b 05 b6 fb 45 76 <48> 8b 70 08 40 f6 c6 3f 74 0b 4c 89 f7 5b 41 5e e9 11 db aa f7 48
RSP: 0018:ffffc900025a7f08 EFLAGS: 00000286
RAX: ffff888072fd5940 RBX: 0000000000000141 RCX: d30c55e2b6d4b100
RDX: dffffc0000000000 RSI: ffffffff8a2b2780 RDI: ffffffff8a79f980
RBP: ffffc900025a7f48 R08: ffff8880b903b30b R09: 1ffff11017207661
R10: dffffc0000000000 R11: ffffed1017207662 R12: 0000000000000000
R13: 0000000000000000 R14: ffffc900025a7f58 R15: 0000000000000000
 do_syscall_64+0x24/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f2212a70799
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:00007f2210cca028 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: 00007f2212ce9fa0 RCX: 00007f2212a70799
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007f2212b06bd9 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f2212cea038 R14: 00007f2212ce9fa0 R15: 00007ffdc016cdf8
 </TASK>

Crashes (6):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
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.