syzbot


INFO: rcu detected stall in clock_nanosleep

Status: upstream: reported on 2025/12/21 12:05
Reported-by: syzbot+7f2ffeff791dbe94e0a7@syzkaller.appspotmail.com
First crash: 108d, last: 6d17h
Similar bugs (11)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: rcu detected stall in sys_clock_nanosleep (5) kernel 1 C error done 105 78d 965d 0/29 upstream: reported C repro on 2023/08/17 09:25
linux-5.15 INFO: rcu detected stall in sys_clock_nanosleep (3) 1 6 178d 441d 0/3 auto-obsoleted due to no activity on 2026/01/20 16:04
linux-5.15 INFO: rcu detected stall in clock_nanosleep origin:lts-only 1 syz error 2 36d 50d 0/3 upstream: reported syz repro on 2026/02/17 07:30
linux-5.15 INFO: rcu detected stall in sys_clock_nanosleep 1 1 940d 940d 0/3 auto-obsoleted due to no activity on 2023/12/20 18:13
linux-6.1 INFO: rcu detected stall in sys_clock_nanosleep (2) 1 4 664d 818d 0/3 auto-obsoleted due to no activity on 2024/09/21 09:26
upstream INFO: rcu detected stall in sys_clock_nanosleep (4) kernel 1 6 1288d 1409d 0/29 auto-obsoleted due to no activity on 2022/12/31 21:43
upstream INFO: rcu detected stall in sys_clock_nanosleep (3) kernel 1 3 1586d 1595d 0/29 closed as invalid on 2022/02/08 10:00
upstream INFO: rcu detected stall in sys_clock_nanosleep kernel 1 1 1841d 1841d 0/29 auto-closed as invalid on 2021/06/22 18:23
linux-6.1 INFO: rcu detected stall in sys_clock_nanosleep 1 1 1116d 1116d 0/3 auto-obsoleted due to no activity on 2023/07/17 12:13
upstream INFO: rcu detected stall in sys_clock_nanosleep (2) kernel 1 1 1718d 1718d 0/29 auto-closed as invalid on 2021/10/22 22:53
linux-5.15 INFO: rcu detected stall in sys_clock_nanosleep (2) 1 2 743d 816d 0/3 auto-obsoleted due to no activity on 2024/07/04 20:17

Sample crash report:
rcu: INFO: rcu_preempt detected expedited stalls on CPUs/tasks: { 1-.... } 2656 jiffies s: 100089 root: 0x2/.
rcu: blocking rcu_node structures (internal RCU debug):
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 22290 Comm: syz-executor Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:irqtime_account_irq+0x1/0x1b0 kernel/sched/cputime.c:50
Code: ff 0f 1f 84 00 00 00 00 00 c6 05 69 cb 41 0e 01 c3 0f 1f 84 00 00 00 00 00 c6 05 59 cb 41 0e 00 c3 0f 1f 84 00 00 00 00 00 55 <41> 57 41 56 41 55 41 54 53 89 f5 49 89 fe e8 3c 45 ce 08 89 c3 83
RSP: 0018:ffffc900001e08b0 EFLAGS: 00000046
RAX: 0000000000000000 RBX: ffffc900001e08d8 RCX: 9b3feea67c386f00
RDX: 0000000000000000 RSI: 0000000000010000 RDI: ffff888079ab0000
RBP: 0000000000000000 R08: ffffffff8e1fdeef R09: 1ffffffff1c3fbdd
R10: dffffc0000000000 R11: fffffbfff1c3fbde R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
FS:  0000555567f78500(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000008000 CR3: 0000000065119000 CR4: 00000000003506e0
DR0: 0000200000000300 DR1: 0000200000000300 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 instr_sysvec_irq_work arch/x86/kernel/irq_work.c:17 [inline]
 sysvec_irq_work+0x45/0xc0 arch/x86/kernel/irq_work.c:17
 asm_sysvec_irq_work+0x16/0x20 arch/x86/include/asm/idtentry.h:728
RIP: 0010:rcu_read_unlock_special+0x7f/0x510 kernel/rcu/tree_plugin.h:685
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 d2 33 95 7e 41 f7 c6 00 00 f0 00 74 40 <48> c7 44 24 40 0e 36 e0 45 4a c7 04 2b 00 00 00 00 42 c7 44 2b 08
RSP: 0018:ffffc900001e0980 EFLAGS: 00000206
RAX: 9b3feea67c386f00 RBX: 1ffff9200003c138 RCX: 9b3feea67c386f00
RDX: dffffc0000000000 RSI: ffffffff8a8c10a0 RDI: ffffffff8adf0d20
RBP: ffffc900001e0a80 R08: ffffffff90af732f R09: 1ffffffff215ee65
R10: dffffc0000000000 R11: fffffbfff215ee66 R12: 0000000000000246
R13: dffffc0000000000 R14: ffff8880b8f3b900 R15: 0000000000000002
 __rcu_read_unlock+0x78/0xd0 kernel/rcu/tree_plugin.h:426
 rcu_read_unlock include/linux/rcupdate.h:823 [inline]
 hsr_announce+0x2ca/0x340 net/hsr/hsr_device.c:407
 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_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline]
 sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1118
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:finish_task_switch+0x26a/0x8f0 kernel/sched/core.c:5124
Code: 0f 84 3b 01 00 00 48 85 db 0f 85 5a 01 00 00 0f 1f 44 00 00 4c 8b 75 d0 4c 89 e7 e8 00 2c de 08 e8 8b 2c 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:ffffc900039d7a18 EFLAGS: 00000286
RAX: 9b3feea67c386f00 RBX: 0000000000000000 RCX: 9b3feea67c386f00
RDX: dffffc0000000000 RSI: ffffffff8a8c10a0 RDI: ffffffff8adf0d20
RBP: ffffc900039d7a70 R08: ffff8880b8f3580b R09: 1ffff110171e6b01
R10: dffffc0000000000 R11: ffffed10171e6b02 R12: ffff888079ab0000
R13: dffffc0000000000 R14: ffff88802be51dc0 R15: ffff8880b8f3b5d0
 context_switch kernel/sched/core.c:5248 [inline]
 __schedule+0x11d9/0x40e0 kernel/sched/core.c:6562
 schedule+0xb9/0x180 kernel/sched/core.c:6638
 do_nanosleep+0x1a9/0x600 kernel/time/hrtimer.c:2088
 hrtimer_nanosleep+0x171/0x370 kernel/time/hrtimer.c:2136
 __do_sys_clock_nanosleep kernel/time/posix-timers.c:1314 [inline]
 __se_sys_clock_nanosleep+0x30b/0x3a0 kernel/time/posix-timers.c:1291
 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: 0033:0x7f2d3115d04e
Code: 08 0f 85 a5 a8 ff ff 49 89 fb 48 89 f0 48 89 d7 48 89 ce 4c 89 c2 4d 89 ca 4c 8b 44 24 08 4c 8b 4c 24 10 4c 89 5c 24 08 0f 05 <c3> 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 80 00 00 00 00 48 83 ec 08
RSP: 002b:00007ffd54fbd418 EFLAGS: 00000246 ORIG_RAX: 00000000000000e6
RAX: ffffffffffffffda RBX: 0000555567f78500 RCX: 00007f2d3115d04e
RDX: 00007ffd54fbd470 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007ffd54fbd4dc R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000001388
R13: 00000000000927c0 R14: 000000000011b166 R15: 00007ffd54fbd530
 </TASK>

Crashes (6):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/04/02 04:06 linux-6.1.y 1989cd3d56e2 0cb124d5 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: rcu detected stall in clock_nanosleep
2026/03/23 06:20 linux-6.1.y f2ddafa93a25 5b92003d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: rcu detected stall in clock_nanosleep
2026/03/20 09:01 linux-6.1.y f2ddafa93a25 2f245add .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: rcu detected stall in clock_nanosleep
2026/02/09 02:10 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 clock_nanosleep
2026/02/03 17:23 linux-6.1.y cd9b81672742 6df4c87a .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: rcu detected stall in clock_nanosleep
2025/12/21 12:04 linux-6.1.y 50cbba13faa2 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: rcu detected stall in clock_nanosleep
* Struck through repros no longer work on HEAD.