INFO: task hung in rcu_is

INFO: task hung in rcu_is_watching (3)

Status: auto-obsoleted due to no activity on 2025/11/29 19:41
Subsystems: kernel
[Documentation on labels]
First crash: 220d, last: 209d

▶ ▼ Similar bugs (2)

Kernel	Title	Rank 🛈	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
upstream	INFO: task hung in rcu_is_watching (2) kernel	1				1	483d	483d	0/29	auto-obsoleted due to no activity on 2025/02/28 17:14
upstream	INFO: task hung in rcu_is_watching kernel	1				1	593d	593d	0/29	auto-obsoleted due to no activity on 2024/11/10 17:08

Sample crash report:

INFO: task kworker/R-ipv6_:3200 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/R-ipv6_ state:D stack:25848 pid:3200  tgid:3200  ppid:2      task_flags:0x4208060 flags:0x00004000
Workqueue: ipv6_addrconf addrconf_dad_work
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5357 [inline]
 __schedule+0x1190/0x5de0 kernel/sched/core.c:6961
 __schedule_loop kernel/sched/core.c:7043 [inline]
 schedule+0xe7/0x3a0 kernel/sched/core.c:7058
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7115
 __mutex_lock_common kernel/locking/mutex.c:676 [inline]
 __mutex_lock+0x81b/0x1060 kernel/locking/mutex.c:760
 rcu_is_watching_curr_cpu include/linux/context_tracking.h:128 [inline]
 rcu_is_watching+0x12/0xc0 kernel/rcu/tree.c:751

Crashes (3):
Time	Kernel	Commit	Syzkaller	Config	Log	Report	VM info	Assets (help?)	Manager	Title
2025/08/20 17:06	upstream	b19a97d57c15	bd178e57	.config	console log	report	info	[disk image] [vmlinux] [kernel image]	ci-upstream-kasan-gce-selinux-root	INFO: task hung in rcu_is_watching
2025/08/31 19:33	linux-next	7fa4d8dc380f	807a3b61	.config	console log	report	info	[disk image] [vmlinux] [kernel image]	ci-upstream-rust-kasan-gce	INFO: task hung in rcu_is_watching
2025/08/22 22:13	linux-next	7fa4d8dc380f	bf27483f	.config	console log	report	info	[disk image] [vmlinux] [kernel image]	ci-upstream-linux-next-kasan-gce-root	INFO: task hung in rcu_is_watching

* ~~Struck through~~ repros no longer work on HEAD.