INFO: rcu detected stall in schedule_timeout

Status: upstream: reported C repro on 2024/05/22 14:45
Bug presence: origin:upstream
[Documentation on labels]
Reported-by: syzbot+7cb65445f1326f641b08@syzkaller.appspotmail.com
First crash: 796d, last: 8d06h
Fix bisection: the issue occurs on the latest tested release (bisect log)
  
▶ ▼ Bug presence (1)
Date Name Commit Repro Result
2024/05/23 upstream (ToT) c760b3725e52 C [report] INFO: rcu detected stall in schedule_timeout
▶ ▼ Similar bugs (10)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: rcu detected stall in schedule_timeout (3) cgroups mm 1 11 2392d 2392d 0/29 closed as invalid on 2020/01/09 08:13
upstream INFO: rcu detected stall in schedule_timeout (7) prio:low kernel 1 C error error 49 2d10h 625d 0/29 upstream: reported C repro on 2024/11/09 08:24
linux-6.1 INFO: rcu detected stall in schedule_timeout (2) origin:lts-only 1 C inconclusive 6 70d 327d 0/3 upstream: reported C repro on 2025/09/02 23:57
upstream INFO: rcu detected stall in schedule_timeout (2) kernel 1 2 2392d 2392d 0/29 closed as invalid on 2020/01/08 05:23
upstream INFO: rcu detected stall in schedule_timeout (4) kernel 1 1 1097d 1097d 0/29 closed as invalid on 2023/09/01 06:44
linux-6.1 INFO: rcu detected stall in schedule_timeout 1 28 765d 830d 0/3 auto-obsoleted due to no activity on 2024/08/31 04:44
upstream INFO: rcu detected stall in schedule_timeout (5) kernel 1 2 1002d 1038d 0/29 auto-obsoleted due to no activity on 2024/01/26 16:31
upstream INFO: rcu detected stall in schedule_timeout cgroups mm 1 69 2427d 2428d 0/29 closed as invalid on 2019/12/04 14:14
upstream INFO: rcu detected stall in schedule_timeout (6) usb 1 C done 40 644d 801d 28/29 fixed on 2024/10/22 11:57
linux-6.6 INFO: rcu detected stall in schedule_timeout origin:upstream 1 C error 8 30d 264d 0/2 upstream: reported C repro on 2025/11/04 19:17
▶ ▼ Last patch testing requests (10)
Created Duration User Patch Repo Result
2026/07/19 08:38 17m retest repro linux-5.15.y report log
2026/07/19 08:38 17m retest repro linux-5.15.y report log
2026/07/19 08:38 21m retest repro linux-5.15.y report log
2026/06/11 04:25 17m retest repro linux-5.15.y report log
2026/05/18 03:16 16m retest repro linux-5.15.y report log
2026/04/28 05:12 18m retest repro linux-5.15.y report log
2026/04/28 05:12 20m retest repro linux-5.15.y report log
2026/04/28 05:12 21m retest repro linux-5.15.y report log
2026/03/23 17:22 11m retest repro linux-5.15.y report log
2026/03/07 12:01 11m retest repro linux-5.15.y report log
▶ ▼ Fix bisection attempts (14)
Created Duration User Patch Repo Result
2026/01/11 18:15 2h28m bisect fix linux-5.15.y OK (0) job log
2025/12/09 03:03 3h13m bisect fix linux-5.15.y OK (0) job log log
2025/11/07 09:13 2h33m bisect fix linux-5.15.y OK (0) job log log
2025/07/28 12:27 1h21m bisect fix linux-5.15.y OK (0) job log log
2025/06/27 16:40 2h07m bisect fix linux-5.15.y OK (0) job log log
2025/05/28 13:53 1h57m bisect fix linux-5.15.y OK (0) job log log
2025/04/24 11:55 2h20m bisect fix linux-5.15.y OK (0) job log log
2025/03/20 08:51 2h13m bisect fix linux-5.15.y OK (0) job log log
2025/02/17 10:09 1h32m bisect fix linux-5.15.y OK (0) job log log
2025/01/17 09:51 1h35m bisect fix linux-5.15.y OK (0) job log log
2024/11/28 09:00 1h06m bisect fix linux-5.15.y OK (0) job log log
2024/10/20 04:58 1h50m bisect fix linux-5.15.y OK (0) job log log
2024/09/03 16:59 1h37m bisect fix linux-5.15.y OK (0) job log log
2024/07/27 12:36 1h26m bisect fix linux-5.15.y OK (0) job log log

Sample crash report:
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P4203/1:b..l
	(detected by 0, t=10502 jiffies, g=3921, q=50)
task:syz-executor374 state:R  running task     stack:29312 pid: 4203 ppid:  4191 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11bb/0x4390 kernel/sched/core.c:6395
 preempt_schedule_common+0x82/0xd0 kernel/sched/core.c:6571
 preempt_schedule+0xa7/0xb0 kernel/sched/core.c:6596
 preempt_schedule_thunk+0x16/0x18 arch/x86/entry/thunk_64.S:34
 __raw_spin_unlock include/linux/spinlock_api_smp.h:152 [inline]
 _raw_spin_unlock+0x36/0x40 kernel/locking/spinlock.c:186
 spin_unlock include/linux/spinlock.h:403 [inline]
 filemap_map_pages+0x1031/0x1390 mm/filemap.c:3353
 do_fault_around mm/memory.c:4243 [inline]
 do_read_fault mm/memory.c:4258 [inline]
 do_fault mm/memory.c:4392 [inline]
 handle_pte_fault mm/memory.c:4650 [inline]
 __handle_mm_fault mm/memory.c:4785 [inline]
 handle_mm_fault+0x2580/0x43c0 mm/memory.c:4883
 do_user_addr_fault+0x489/0xc80 arch/x86/mm/fault.c:1357
 handle_page_fault arch/x86/mm/fault.c:1445 [inline]
 exc_page_fault+0x60/0x100 arch/x86/mm/fault.c:1501
 asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:606
RIP: 0033:0x7fd9aff93fa0
RSP: 002b:00007fd9aff33198 EFLAGS: 00010246
RAX: fffffffffffffec0 RBX: 00007fd9aff336c0 RCX: 00007fd9affaad99
RDX: 00007fd9aff33d78 RSI: 0000000000000058 RDI: 00007fd9aff336c0
RBP: 0000000000000000 R08: 00007fd9aff336c0 R09: 00007ffca61df647
R10: 0000000000000008 R11: 0000000000000206 R12: ffffffffffffffb0
R13: 0000000000000000 R14: 00007ffca61df560 R15: 00007ffca61df648
 </TASK>
rcu: rcu_preempt kthread starved for 10518 jiffies! g3921 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0
rcu: 	Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
rcu: RCU grace-period kthread stack dump:
task:rcu_preempt     state:R  running task     stack:28032 pid:   15 ppid:     2 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11bb/0x4390 kernel/sched/core.c:6395
 preempt_schedule_irq+0xb1/0x150 kernel/sched/core.c:6799
 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:timer_delete_sync+0x158/0x260 kernel/time/timer.c:1403
Code: 00 4d 85 ed 75 16 e8 67 9c 10 00 eb 15 e8 60 9c 10 00 e8 9b bf 41 08 4d 85 ed 74 ea e8 51 9c 10 00 fb 65 44 8b 35 f0 40 9b 7e <44> 89 f6 81 e6 00 00 0f 00 31 ff e8 98 9f 10 00 41 81 e6 00 00 0f
RSP: 0018:ffffc90000d47b00 EFLAGS: 00000293
RAX: ffffffff81672ecf RBX: ffffc90000d47be0 RCX: ffff88813feabb80
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc90000d47bb0 R08: dffffc0000000000 R09: fffffbfff1ad323e
R10: fffffbfff1ad323e R11: 1ffffffff1ad323d R12: dffffc0000000000
R13: 0000000000000200 R14: 0000000080000000 R15: 1ffff920001a8f60
 del_timer_sync include/linux/timer.h:198 [inline]
 schedule_timeout+0x164/0x280 kernel/time/timer.c:1915
 rcu_gp_fqs_loop+0x29e/0x11b0 kernel/rcu/tree.c:1972
 rcu_gp_kthread+0x98/0x350 kernel/rcu/tree.c:2145
 kthread+0x436/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
NMI backtrace for cpu 0
CPU: 0 PID: 4199 Comm: syz-executor374 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Call Trace:
 <IRQ>
 dump_stack_lvl+0x168/0x230 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x397/0x3d0 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x163/0x280 lib/nmi_backtrace.c:62
 trigger_single_cpu_backtrace include/linux/nmi.h:166 [inline]
 rcu_check_gp_kthread_starvation+0x1cd/0x250 kernel/rcu/tree_stall.h:487
 print_other_cpu_stall+0x10c8/0x1220 kernel/rcu/tree_stall.h:592
 check_cpu_stall kernel/rcu/tree_stall.h:745 [inline]
 rcu_pending kernel/rcu/tree.c:3936 [inline]
 rcu_sched_clock_irq+0x831/0x1110 kernel/rcu/tree.c:2619
 update_process_times+0x193/0x200 kernel/time/timer.c:1818
 tick_sched_handle kernel/time/tick-sched.c:254 [inline]
 tick_sched_timer+0x37d/0x560 kernel/time/tick-sched.c:1473
 __run_hrtimer kernel/time/hrtimer.c:1690 [inline]
 __hrtimer_run_queues+0x4fe/0xc40 kernel/time/hrtimer.c:1754
 hrtimer_interrupt+0x3bb/0x8d0 kernel/time/hrtimer.c:1816
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1097 [inline]
 __sysvec_apic_timer_interrupt+0x137/0x4a0 arch/x86/kernel/apic/apic.c:1114
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline]
 sysvec_apic_timer_interrupt+0x9b/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:lock_acquire+0x1f2/0x3f0 kernel/locking/lockdep.c:5627
Code: 00 9c 8f 84 24 80 00 00 00 f6 84 24 81 00 00 00 02 0f 85 f6 00 00 00 41 f7 c6 00 02 00 00 74 01 fb 48 c7 44 24 60 0e 36 e0 45 <4b> c7 44 3d 00 00 00 00 00 66 43 c7 44 3d 09 00 00 43 c6 44 3d 0b
RSP: 0018:ffffc90002eaf9c0 EFLAGS: 00000206
RAX: 0000000000000001 RBX: 0000000000000000 RCX: 6356f938c2ca3700
RDX: 0000000000000000 RSI: ffffffff8a0b2ac0 RDI: ffffffff8a59a480
RBP: ffffc90002eafad8 R08: dffffc0000000000 R09: fffffbfff1ff781f
R10: fffffbfff1ff781f R11: 1ffffffff1ff781e R12: ffff8880793c8128
R13: 1ffff920005d5f44 R14: 0000000000000246 R15: dffffc0000000000
 __might_fault+0xb3/0x110 mm/memory.c:5357
 __copy_to_user include/linux/uaccess.h:143 [inline]
 save_xstate_epilog arch/x86/kernel/fpu/signal.c:104 [inline]
 copy_fpstate_to_sigframe+0x882/0xb90 arch/x86/kernel/fpu/signal.c:217
 get_sigframe arch/x86/kernel/signal.c:295 [inline]
 __setup_rt_frame arch/x86/kernel/signal.c:471 [inline]
 setup_rt_frame arch/x86/kernel/signal.c:780 [inline]
 handle_signal arch/x86/kernel/signal.c:824 [inline]
 arch_do_signal_or_restart+0x67a/0x1300 arch/x86/kernel/signal.c:869
 handle_signal_work kernel/entry/common.c:154 [inline]
 exit_to_user_mode_loop+0x9e/0x130 kernel/entry/common.c:178
 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:214
 __syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline]
 syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:307
 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fd9aff7afc7
Code: 14 25 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 1c 00 00 90 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 b0 ff ff ff f7 d8 64 89
RSP: 002b:00007fd9aff33178 EFLAGS: 00000246
RAX: 00000000000000ca RBX: 00007fd9afffd308 RCX: 00007fd9aff7afc9
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007fd9afffd308
RBP: 00007fd9afffd300 R08: 00007fd9aff336c0 R09: 00007fd9aff336c0
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fd9afffd30c
R13: 0000000000000000 R14: 00007ffca61df560 R15: 00007ffca61df648
 </TASK>

Crashes (13):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/09/13 04:10 linux-5.15.y 43bb85222e53 e2beed91 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in schedule_timeout
2025/09/13 00:10 linux-5.15.y 43bb85222e53 e2beed91 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in schedule_timeout
2024/05/23 05:50 linux-5.15.y 83655231580b 4d098039 .config console log report syz C [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in schedule_timeout
2025/09/13 06:02 linux-5.15.y 43bb85222e53 e2beed91 .config console log report syz / log [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in schedule_timeout
2025/09/01 03:21 linux-5.15.y 01879f56bdde 807a3b61 .config console log report syz / log [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in schedule_timeout
2026/02/21 10:18 linux-5.15.y 3330a8d33e08 6e7b5511 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in schedule_timeout
2024/06/10 21:57 linux-5.15.y c61bd26ae81a 048c640a .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in schedule_timeout
2024/06/10 21:53 linux-5.15.y c61bd26ae81a 048c640a .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in schedule_timeout
2024/05/23 03:37 linux-5.15.y 83655231580b 4d098039 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in schedule_timeout
2024/05/22 14:44 linux-5.15.y 83655231580b 4d098039 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in schedule_timeout
2024/12/05 01:45 linux-5.15.y 0a51d2d4527b b50eb251 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 INFO: rcu detected stall in schedule_timeout
2024/09/18 12:18 linux-5.15.y 3a5928702e71 c673ca06 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 INFO: rcu detected stall in schedule_timeout
2024/08/01 21:04 linux-5.15.y 7e89efd3ae1c 1e9c4cf3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 INFO: rcu detected stall in schedule_timeout
* Struck through repros no longer work on HEAD.