syzbot


INFO: rcu detected stall in irqentry_exit

Status: upstream: reported C repro on 2025/08/25 11:36
Bug presence: origin:lts-only
[Documentation on labels]
Reported-by: syzbot+b88c7fb221e9dae9caf0@syzkaller.appspotmail.com
First crash: 104d, last: 11d
Bug presence (2)
Date Name Commit Repro Result
2025/11/20 linux-6.6.y (ToT) 0a805b6ea8cd C [report] INFO: rcu detected stall in smp_call_function
2025/11/20 upstream (ToT) fd95357fd8c6 C Didn't crash
Similar bugs (5)
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 477d 477d 0/3 auto-obsoleted due to no activity on 2024/11/25 13:22
linux-5.15 INFO: rcu detected stall in irqentry_exit (2) 1 4 3h14m 81d 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 1 26d 26d 0/3 upstream: reported syz repro on 2025/11/10 20:44
linux-5.15 INFO: rcu detected stall in irqentry_exit 1 1 544d 544d 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 353d 349d 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=3de4/1/0x4000000000000000 softirq=12521/12522 fqs=4296
rcu: 	         hardirqs   softirqs   csw/system
rcu: 	 number:  1038609          0            0
rcu: 	cputime:    20303      32175           17   ==> 52480(ms)
rcu: 	(t=10500 jiffies g=9873 q=793 ncpus=2)
CPU: 0 PID: 5953 Comm: syz.0.17 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline]
RIP: 0010:_raw_spin_unlock_irqrestore+0xa9/0x110 kernel/locking/spinlock.c:194
Code: 74 05 e8 ea 7c 13 f7 48 c7 44 24 20 00 00 00 00 9c 8f 44 24 20 f6 44 24 21 02 75 4b f7 c3 00 02 00 00 74 01 fb bf 01 00 00 00 <e8> f2 f8 e2 f6 65 8b 05 e3 41 8b 75 85 c0 74 3c 48 c7 04 24 0e 36
RSP: 0018:ffffc90000007400 EFLAGS: 00000206
RAX: e09796298706d200 RBX: 0000000000000a06 RCX: e09796298706d200
RDX: dffffc0000000000 RSI: ffffffff8aaabce0 RDI: 0000000000000001
RBP: ffffc90000007480 R08: ffffffff90da85d7 R09: 1ffffffff21b50ba
R10: dffffc0000000000 R11: fffffbfff21b50bb R12: dffffc0000000000
R13: 1ffff11005620322 R14: ffff88802dd25868 R15: 1ffff92000000e80
FS:  00005555564d7500(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000007b69f000 CR4: 00000000003506f0
Call Trace:
 <IRQ>
 __ieee80211_queue_skb_to_iface net/mac80211/rx.c:231 [inline]
 ieee80211_queue_skb_to_iface net/mac80211/rx.c:243 [inline]
 ieee80211_rx_h_mgmt+0x4ae/0x6f0 net/mac80211/rx.c:3989
 ieee80211_rx_handlers+0x64f0/0xb0c0 net/mac80211/rx.c:4147
 ieee80211_invoke_rx_handlers net/mac80211/rx.c:4177 [inline]
 ieee80211_prepare_and_rx_handle+0x25fe/0x61d0 net/mac80211/rx.c:5035
 ieee80211_rx_for_interface net/mac80211/rx.c:5120 [inline]
 __ieee80211_rx_handle_packet net/mac80211/rx.c:5293 [inline]
 ieee80211_rx_list+0x26c9/0x2fe0 net/mac80211/rx.c:5428
 ieee80211_rx_napi+0x1aa/0x3c0 net/mac80211/rx.c:5451
 ieee80211_rx include/net/mac80211.h:4971 [inline]
 ieee80211_handle_queued_frames+0x106/0x1a0 net/mac80211/main.c:319
 tasklet_action_common+0x2eb/0x4c0 kernel/softirq.c:809
 handle_softirqs+0x280/0x820 kernel/softirq.c:578
 __do_softirq kernel/softirq.c:612 [inline]
 invoke_softirq kernel/softirq.c:452 [inline]
 __irq_exit_rcu+0xc7/0x190 kernel/softirq.c:661
 irq_exit_rcu+0x9/0x20 kernel/softirq.c:673
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1088 [inline]
 sysvec_apic_timer_interrupt+0xa4/0xc0 arch/x86/kernel/apic/apic.c:1088
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:finish_task_switch+0x26a/0x920 kernel/sched/core.c:5254
Code: 0f 84 37 01 00 00 48 85 db 0f 85 56 01 00 00 0f 1f 44 00 00 4c 8b 75 d0 4c 89 e7 e8 70 25 1c 09 e8 1b a3 2f 00 fb 4c 8b 65 c0 <49> 8d bc 24 f8 15 00 00 48 89 f8 48 c1 e8 03 42 0f b6 04 28 84 c0
RSP: 0018:ffffc90003f67978 EFLAGS: 00000286
RAX: e09796298706d200 RBX: 0000000000000000 RCX: e09796298706d200
RDX: dffffc0000000000 RSI: ffffffff8aaabce0 RDI: ffffffff8afc6b00
RBP: ffffc90003f679d0 R08: ffffffff8e4a8d6f R09: 1ffffffff1c951ad
R10: dffffc0000000000 R11: fffffbfff1c951ae R12: ffff88802b548000
R13: dffffc0000000000 R14: ffff88801ab23c00 R15: ffff8880b8e3ccc8
 context_switch kernel/sched/core.c:5383 [inline]
 __schedule+0x14da/0x44d0 kernel/sched/core.c:6699
 preempt_schedule_irq+0xb5/0x140 kernel/sched/core.c:7009
 irqentry_exit+0x67/0x70 kernel/entry/common.c:438
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:perf_release+0x0/0x40 kernel/events/core.c:5510
Code: 00 48 8b 54 24 38 e9 76 fa ff ff e8 2a d9 d5 ff e9 2f fa ff ff e8 20 d9 d5 ff 4c 89 e7 e8 08 0f b4 08 0f 0b 66 0f 1f 44 00 00 <f3> 0f 1e fa 53 48 89 f3 e8 03 d9 d5 ff 48 81 c3 b0 01 00 00 48 89
RSP: 0018:ffffc90003f67d58 EFLAGS: 00010293
RAX: ffffffff81ec51bb RBX: ffff888076cbaf00 RCX: ffff88802b548000
RDX: 0000000000000000 RSI: ffff888076cbaf00 RDI: ffff888148c51e60
RBP: 0000000000000000 R08: ffff888140afc787 R09: 1ffff1102815f8f0
R10: dffffc0000000000 R11: ffffed102815f8f1 R12: 1ffff1100ed97613
R13: ffffffff81afb680 R14: ffff888076cbb098 R15: ffff888148c51e60
 __fput+0x234/0x970 fs/file_table.c:384
 task_work_run+0x1ce/0x250 kernel/task_work.c:239
 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
 exit_to_user_mode_loop+0xe6/0x110 kernel/entry/common.c:177
 exit_to_user_mode_prepare+0xf6/0x180 kernel/entry/common.c:210
 __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline]
 syscall_exit_to_user_mode+0x1a/0x50 kernel/entry/common.c:302
 do_syscall_64+0x61/0xb0 arch/x86/entry/common.c:87
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fb84c18f6c9
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:00007ffd8d61d498 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 000000000001b118 RCX: 00007fb84c18f6c9
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 0000000000000000 R08: 0000000000000001 R09: 000000028d61d78f
R10: 0000001b2cc20000 R11: 0000000000000246 R12: 00007fb84c3e5fac
R13: 00007fb84c3e5fa0 R14: ffffffffffffffff R15: 0000000000000005
 </TASK>

Crashes (5):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/11/19 04:49 linux-6.6.y 0a805b6ea8cd ef766cd7 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan-perf INFO: rcu detected stall in irqentry_exit
2025/11/26 12:19 linux-6.6.y 1e89a1be4fe9 64219f15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan-perf INFO: rcu detected stall in irqentry_exit
2025/10/10 14:21 linux-6.6.y e617101e5626 ff1712fe .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan-perf INFO: rcu detected stall in irqentry_exit
2025/08/28 14:10 linux-6.6.y bb9c90ab9c5a e12e5ba4 .config console log report syz / log [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan-perf INFO: rcu detected stall in irqentry_exit
2025/08/25 11:35 linux-6.6.y bb9c90ab9c5a bf27483f .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan-perf INFO: rcu detected stall in irqentry_exit
* Struck through repros no longer work on HEAD.