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: 90d, last: 1d10h
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 60d 947d 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 160d 423d 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 18d 32d 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 922d 922d 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 646d 800d 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 1270d 1390d 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 1568d 1577d 0/29 closed as invalid on 2022/02/08 10:00
upstream INFO: rcu detected stall in sys_clock_nanosleep kernel 1 1 1823d 1823d 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 1098d 1098d 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 1700d 1700d 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 724d 797d 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: { 0-.... } 2673 jiffies s: 28061 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: 6522 Comm: syz.1.588 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:check_preemption_disabled+0x4b/0x110 lib/smp_processor_id.c:55
Code: 0d f2 54 d5 75 f7 c1 ff ff ff 7f 74 1f 65 48 8b 0c 25 28 00 00 00 48 3b 4c 24 08 0f 85 c4 00 00 00 48 83 c4 10 5b 41 5e 41 5f <5d> c3 48 c7 04 24 00 00 00 00 9c 8f 04 24 f7 04 24 00 02 00 00 74
RSP: 0018:ffffc900000079b8 EFLAGS: 00000086
RAX: 0000000000000000 RBX: ffff8880b8e277b0 RCX: d13297b92e665800
RDX: 1ffffffff1f41600 RSI: ffffffff8adf0f40 RDI: ffffffff8adf0f00
RBP: 0000000000010000 R08: ffffffff8fa0b008 R09: ffffffff8fa0b018
R10: ffffffff8fa0b010 R11: ffffffff8fa0b003 R12: dffffc0000000000
R13: 0000000000001077 R14: ffff888030dcbb80 R15: 0000003dd0f17bbf
FS:  0000555568bc9500(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000002ee0 CR3: 000000007808a000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 irqtime_account_delta kernel/sched/cputime.c:36 [inline]
 irqtime_account_irq+0x16b/0x1b0 kernel/sched/cputime.c:73
 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 e2 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:ffffc90000007ac0 EFLAGS: 00000206
RAX: d13297b92e665800 RBX: 1ffff92000000f60 RCX: d13297b92e665800
RDX: dffffc0000000000 RSI: ffffffff8a8c1220 RDI: ffffffff8adf0f60
RBP: ffffc90000007bb0 R08: ffff8880b8e3580b R09: 1ffff110171c6b01
R10: dffffc0000000000 R11: ffffed10171c6b02 R12: 0000000000000246
R13: dffffc0000000000 R14: ffff8880b8e3b900 R15: 0000000000000001
 __rcu_read_unlock+0x78/0xd0 kernel/rcu/tree_plugin.h:426
 rcu_read_unlock include/linux/rcupdate.h:823 [inline]
 ieee80211_iterate_active_interfaces_atomic+0x156/0x170 net/mac80211/util.c:826
 mac80211_hwsim_beacon+0xb7/0x1b0 drivers/net/wireless/mac80211_hwsim.c:2147
 __run_hrtimer kernel/time/hrtimer.c:1747 [inline]
 __hrtimer_run_queues+0x54a/0xd50 kernel/time/hrtimer.c:1811
 hrtimer_run_softirq+0x183/0x2a0 kernel/time/hrtimer.c:1828
 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:native_save_fl arch/x86/include/asm/irqflags.h:35 [inline]
RIP: 0010:arch_local_save_flags arch/x86/include/asm/irqflags.h:70 [inline]
RIP: 0010:arch_local_irq_save arch/x86/include/asm/irqflags.h:106 [inline]
RIP: 0010:lock_is_held_type+0x64/0x190 kernel/locking/lockdep.c:5701
Code: 00 00 00 65 48 8b 1d 1b 67 d5 75 83 bb dc 0a 00 00 00 0f 85 df 00 00 00 41 89 f7 49 89 fe 48 c7 04 24 00 00 00 00 9c 8f 04 24 <4c> 8b 2c 24 fa 48 c7 c7 00 1f 8c 8a e8 eb 12 00 00 65 ff 05 64 71
RSP: 0018:ffffc9000365fbf8 EFLAGS: 00000246
RAX: 0000000000000000 RBX: ffff888030dcbb80 RCX: ffff888030dcbb80
RDX: 0000000000000000 RSI: 00000000ffffffff RDI: ffffffff8cb2d680
RBP: 00000000ffffffff R08: ffffc9000365fdef R09: ffffc9000365fde0
R10: dffffc0000000000 R11: fffff520006cbfbe R12: dffffc0000000000
R13: dffffc0000000000 R14: ffffffff8cb2d680 R15: 00000000ffffffff
 lock_is_held include/linux/lockdep.h:283 [inline]
 __might_resched+0x9b/0x630 kernel/sched/core.c:9931
 __might_fault+0x6d/0x120 mm/memory.c:5848
 _copy_from_user+0x27/0x170 lib/usercopy.c:14
 copy_from_user include/linux/uaccess.h:161 [inline]
 get_timespec64+0x93/0x1b0 kernel/time/time.c:787
 __do_sys_clock_nanosleep kernel/time/posix-timers.c:1303 [inline]
 __se_sys_clock_nanosleep+0x1c3/0x3a0 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: 0033:0x7f7de5f5cfce
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:00007ffe8768d358 EFLAGS: 00000246 ORIG_RAX: 00000000000000e6
RAX: ffffffffffffffda RBX: 0000555568bc9500 RCX: 00007f7de5f5cfce
RDX: 00007ffe8768d3b0 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007f7de6217da0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000003a691
R13: 00007f7de621618c R14: 000000000003a425 R15: 00007ffe8768d4e0
 </TASK>

Crashes (4):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
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.