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INFO: rcu detected stall in schedule_tail (2)

Status: upstream: reported on 2026/05/13 04:49
Reported-by: syzbot+c7ef9668cfa7f53d0211@syzkaller.appspotmail.com
First crash: 2d15h, last: 2d15h
▶ ▼ Similar bugs (10)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: rcu detected stall in schedule_tail (4) arm 1 2 1073d 1150d 0/29 auto-obsoleted due to no activity on 2023/09/05 02:08
linux-6.1 INFO: rcu detected stall in schedule_tail 1 1 671d 671d 0/3 auto-obsoleted due to no activity on 2024/10/21 04:18
upstream INFO: rcu detected stall in schedule_tail (7) mm 1 1 326d 326d 0/29 auto-obsoleted due to no activity on 2025/08/22 04:05
upstream INFO: rcu detected stall in schedule_tail mm 1 145 2354d 2355d 0/29 closed as invalid on 2019/12/04 14:14
upstream INFO: rcu detected stall in schedule_tail (3) cgroups mm 1 40 2319d 2319d 0/29 closed as invalid on 2020/01/09 08:13
linux-6.6 INFO: rcu detected stall in schedule_tail origin:lts-only 1 C error 1 41d 41d 0/2 upstream: reported C repro on 2026/04/04 18:44
upstream INFO: rcu detected stall in schedule_tail (5) mm 1 2 945d 946d 0/29 auto-obsoleted due to no activity on 2024/01/11 06:31
upstream INFO: rcu detected stall in schedule_tail (8) mm 1 C error error 1 110d 108d 0/29 upstream: reported C repro on 2026/01/27 01:07
upstream INFO: rcu detected stall in schedule_tail (6) mm 1 C 8 494d 589d 0/29 auto-obsoleted due to no activity on 2025/04/16 03:50
upstream INFO: rcu detected stall in schedule_tail (2) mm 1 26 2319d 2319d 0/29 closed as invalid on 2020/01/08 05:23

Sample crash report:
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P10488/1:b..l
	(detected by 0, t=10503 jiffies, g=65049, q=30111 ncpus=2)
task:syz-executor    state:R  running task     stack:29936 pid:10488 ppid:4282   flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5245 [inline]
 __schedule+0x11d1/0x40e0 kernel/sched/core.c:6562
 preempt_schedule_irq+0xbb/0x160 kernel/sched/core.c:6874
 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:trace_lock_acquire include/trace/events/lock.h:24 [inline]
RIP: 0010:lock_acquire+0xdc/0x4a0 kernel/locking/lockdep.c:5633
Code: b8 bb 0c 0f 83 a2 01 00 00 45 89 f4 41 c1 ee 06 4a 8d 3c f5 e8 f3 1f 8e be 08 00 00 00 e8 fc 45 6f 00 4c 0f a3 25 bc b6 bb 0c <73> 0d e8 9d 32 08 00 84 c0 0f 84 2e 02 00 00 48 c7 c0 a4 28 20 8e
RSP: 0018:ffffc9000da97dc0 EFLAGS: 00000257
RAX: 0000000000000001 RBX: 0000000000000000 RCX: ffffffff81643d24
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff8e1ff3e8
RBP: ffffc9000da97ed0 R08: ffffffff8e1ff3ef R09: 1ffffffff1c3fe7d
R10: dffffc0000000000 R11: fffffbfff1c3fe7e R12: 0000000000000000
R13: 1ffff92001b52fc4 R14: 0000000000000000 R15: dffffc0000000000
 rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
 rcu_read_lock include/linux/rcupdate.h:791 [inline]
 __task_pid_nr_ns+0x44/0x460 kernel/pid.c:497
 task_pid_vnr include/linux/sched.h:1576 [inline]
 schedule_tail+0x74/0xb0 kernel/sched/core.c:5184
 ret_from_fork+0x8/0x30 arch/x86/entry/entry_64.S:280
 </TASK>

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/05/13 04:48 linux-6.1.y ad16b162f21d a0949470 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in schedule_tail
* Struck through repros no longer work on HEAD.