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INFO: rcu detected stall in call_timer_fn (2)

Status: upstream: reported on 2026/02/09 05:30
Reported-by: syzbot+c6428c3197b4f8889769@syzkaller.appspotmail.com
First crash: 56d, last: 36d
▶ ▼ Similar bugs (14)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream BUG: soft lockup in call_timer_fn net mm 1 19 615d 658d 0/29 auto-obsoleted due to no activity on 2024/10/08 10:43
linux-6.1 INFO: rcu detected stall in call_timer_fn 1 2 541d 612d 0/3 auto-obsoleted due to no activity on 2025/01/21 02:15
linux-4.19 INFO: rcu detected stall in call_timer_fn (2) 1 16 1979d 2253d 0/1 auto-closed as invalid on 2021/03/04 12:30
upstream INFO: rcu detected stall in call_timer_fn (5) net input usb 1 C 9 270d 403d 0/29 upstream: reported C repro on 2025/02/27 04:11
linux-4.14 INFO: rcu detected stall in call_timer_fn (2) 1 1 2042d 2042d 0/1 auto-closed as invalid on 2020/12/31 22:00
linux-5.15 INFO: rcu detected stall in call_timer_fn 1 7 19d 199d 0/3 upstream: reported on 2025/09/20 00:57
upstream INFO: rcu detected stall in call_timer_fn (2) kernel 1 C done error 47 1539d 2395d 0/29 closed as invalid on 2022/02/08 10:46
upstream INFO: rcu detected stall in call_timer_fn bpf net 1 2 2732d 2745d 0/29 closed as dup on 2019/01/02 16:26
linux-4.19 INFO: rcu detected stall in call_timer_fn 1 1 2393d 2393d 0/1 auto-closed as invalid on 2020/01/15 18:43
linux-4.14 INFO: rcu detected stall in call_timer_fn 1 5 2166d 2286d 0/1 auto-closed as invalid on 2020/08/29 09:07
upstream INFO: rcu detected stall in call_timer_fn (4) mm 1 1 796d 796d 0/29 auto-obsoleted due to no activity on 2024/03/31 10:44
upstream INFO: rcu detected stall in call_timer_fn (3) kernel 1 3 1278d 1293d 0/29 auto-obsoleted due to no activity on 2023/01/12 18:45
linux-4.19 BUG: soft lockup in call_timer_fn 1 C error 31 1129d 1732d 0/1 upstream: reported C repro on 2021/07/10 02:48
upstream BUG: soft lockup in call_timer_fn (2) trace 1 1 541d 537d 0/29 auto-obsoleted due to no activity on 2025/01/10 05:15

Sample crash report:
rcu: INFO: rcu_preempt detected expedited stalls on CPUs/tasks: { 0-.... } 2682 jiffies s: 173197 root: 0x1/.
rcu: blocking rcu_node structures (internal RCU debug):
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 7976 Comm: syz.2.8886 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:task_irq_context kernel/locking/lockdep.c:4558 [inline]
RIP: 0010:__lock_acquire+0x47b/0x7d10 kernel/locking/lockdep.c:4987
Code: 85 c0 0f 95 c3 01 db 48 8b 84 24 88 00 00 00 4c 8d b0 c4 0a 00 00 4c 89 f0 48 c1 e8 03 48 89 84 24 d0 00 00 00 42 0f b6 04 00 <84> c0 0f 85 11 63 00 00 31 c0 4c 89 b4 24 b8 00 00 00 41 83 3e 00
RSP: 0018:ffffc900000073e0 EFLAGS: 00000803
RAX: 0000000000000000 RBX: 0000000000000002 RCX: 1ffff11004a128df
RDX: 000000000000005f RSI: 0000000000000000 RDI: ffff8880250946e8
RBP: ffffc90000007630 R08: dffffc0000000000 R09: 0000000000000001
R10: dffffc0000000000 R11: fffffbfff1c3f9a6 R12: ffff8880250946d8
R13: 0000000000000000 R14: ffff888025094644 R15: 000000000000005f
FS:  00007fa415d8e6c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055558cb42a68 CR3: 0000000058940000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 lock_acquire+0x1bb/0x4a0 kernel/locking/lockdep.c:5662
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
 _raw_spin_lock_irqsave+0xb0/0x100 kernel/locking/spinlock.c:162
 hrtimer_interrupt+0x5ba/0x9c0 kernel/time/hrtimer.c:1904
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1107 [inline]
 __sysvec_apic_timer_interrupt+0x153/0x5a0 arch/x86/kernel/apic/apic.c:1124
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline]
 sysvec_apic_timer_interrupt+0x4d/0xc0 arch/x86/kernel/apic/apic.c:1118
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline]
RIP: 0010:_raw_spin_unlock_irqrestore+0xbc/0x120 kernel/locking/spinlock.c:194
Code: c7 44 24 20 00 00 00 00 9c 8f 44 24 20 f7 44 24 20 00 02 00 00 41 c6 04 07 f8 75 4b f7 c3 00 02 00 00 74 01 fb bf 01 00 00 00 <e8> 0f 2c 22 f7 65 8b 05 d0 b0 cb 75 85 c0 74 3c 48 c7 04 24 0e 36
RSP: 0018:ffffc90000007a40 EFLAGS: 00000206
RAX: dffffc0000000004 RBX: 0000000000000a02 RCX: 1d8f01d1351ffc00
RDX: dffffc0000000000 RSI: ffffffff8a8c1220 RDI: 0000000000000001
RBP: ffffc90000007ad0 R08: ffffffff90af52d7 R09: 1ffffffff215ea5a
R10: dffffc0000000000 R11: fffffbfff215ea5b R12: dffffc0000000000
R13: dffffc0000000000 R14: ffff8880b8e28440 R15: 1ffff92000000f48
 __mod_timer+0x91e/0xd00 kernel/time/timer.c:1134
 call_timer_fn+0x1ac/0x670 kernel/time/timer.c:1701
 expire_timers kernel/time/timer.c:1752 [inline]
 __run_timers+0x53e/0x800 kernel/time/timer.c:2023
 run_timer_softirq+0x63/0xf0 kernel/time/timer.c:2036
 handle_softirqs+0x2a1/0x930 kernel/softirq.c:596
 __do_softirq kernel/softirq.c:630 [inline]
 invoke_softirq kernel/softirq.c:470 [inline]
 __irq_exit_rcu+0x13b/0x230 kernel/softirq.c:679
 irq_exit_rcu+0x5/0x20 kernel/softirq.c:691
 instr_sysvec_irq_work arch/x86/kernel/irq_work.c:17 [inline]
 sysvec_irq_work+0x9d/0xc0 arch/x86/kernel/irq_work.c:17
 </IRQ>
 <TASK>
 asm_sysvec_irq_work+0x16/0x20 arch/x86/include/asm/idtentry.h:728
RIP: 0010:preempt_schedule_irq+0xb6/0x160 kernel/sched/core.c:6874
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 f5 a2 23 f7 e8 20 98 53 f7 fb bf 01 00 00 00 <e8> 75 b9 ff ff 43 c6 44 37 08 00 48 c7 44 24 40 00 00 00 00 9c 8f
RSP: 0018:ffffc9000d1cf780 EFLAGS: 00000282
RAX: 1d8f01d1351ffc00 RBX: 0000000000000000 RCX: 1d8f01d1351ffc00
RDX: dffffc0000000000 RSI: ffffffff8a8c1220 RDI: 0000000000000001
RBP: ffffc9000d1cf820 R08: ffffffff90af52e7 R09: 1ffffffff215ea5c
R10: dffffc0000000000 R11: fffffbfff215ea5d R12: 0000000000000000
R13: 0000000000000000 R14: dffffc0000000000 R15: 1ffff92001a39ef0
 irqentry_exit+0x63/0x70 kernel/entry/common.c:439
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:get_current arch/x86/include/asm/current.h:15 [inline]
RIP: 0010:__sanitizer_cov_trace_pc+0x4/0x60 kernel/kcov.c:215
Code: 00 00 00 00 00 90 53 48 89 fb e8 17 00 00 00 48 8b 3d 40 5a 9d 0c 48 89 de 5b e9 47 22 50 00 00 00 cc cc 00 00 cc 48 8b 04 24 <65> 48 8b 0d 14 fa 7f 7e 65 8b 15 15 fa 7f 7e 81 e2 00 01 ff 00 74
RSP: 0018:ffffc9000d1cf8e0 EFLAGS: 00000246
RAX: ffffffff81e41f50 RBX: ffff88807cdd9a80 RCX: 0000000000000002
RDX: ffff888025093b80 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffff88807cdd9aa8 R08: ffffffff8e1fcd2f R09: fffff52001a39ec4
R10: dffffc0000000000 R11: fffffbfff1c3f9a6 R12: 0000000000000000
R13: 0000000000000003 R14: 0000000000000000 R15: 0000000000000000
 acl_permission_check fs/namei.c:349 [inline]
 generic_permission+0x230/0x510 fs/namei.c:407
 do_inode_permission fs/namei.c:468 [inline]
 inode_permission+0x90/0x480 fs/namei.c:528
 may_o_create fs/namei.c:3319 [inline]
 lookup_open fs/namei.c:3453 [inline]
 open_last_lookups fs/namei.c:3558 [inline]
 path_openat+0xbfd/0x2ee0 fs/namei.c:3788
 do_filp_open+0x1f1/0x430 fs/namei.c:3818
 do_sys_openat2+0x150/0x4b0 fs/open.c:1320
 do_sys_open fs/open.c:1336 [inline]
 __do_sys_openat fs/open.c:1352 [inline]
 __se_sys_openat fs/open.c:1347 [inline]
 __x64_sys_openat+0x135/0x160 fs/open.c:1347
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fa414f9c799
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:00007fa415d8e028 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007fa415215fa0 RCX: 00007fa414f9c799
RDX: 00000000000026e1 RSI: 0000200000000180 RDI: ffffffffffffff9c
RBP: 00007fa415032bd9 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fa415216038 R14: 00007fa415215fa0 R15: 00007ffca2b4e9d8
 </TASK>

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/03/01 18:17 linux-6.1.y 779f9571ac3e 43249bac .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: rcu detected stall in call_timer_fn
2026/02/09 05:29 linux-6.1.y 0182cb5b74ee 4c131dc4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: rcu detected stall in call_timer_fn
* Struck through repros no longer work on HEAD.