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INFO: task hung in linkwatch_event

Status: upstream: reported on 2025/07/04 13:16
Reported-by: syzbot+a255043cadd915b831d0@syzkaller.appspotmail.com
First crash: 6d20h, last: 6d20h
▶ ▼ Similar bugs (18)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-5.15 INFO: task hung in linkwatch_event (2) 1 1 152d 152d 0/3 auto-obsoleted due to no activity on 2025/05/19 15:08
linux-6.1 INFO: task hung in linkwatch_event (4) 1 syz 7 28d 120d 0/3 upstream: reported syz repro on 2025/03/13 04:56
android-414 INFO: task hung in linkwatch_event 1 C 7 2063d 2283d 0/1 public: reported C repro on 2019/04/10 16:14
linux-4.14 INFO: task hung in linkwatch_event (2) 1 1 1084d 1084d 0/1 auto-obsoleted due to no activity on 2022/11/19 11:58
android-44 INFO: task hung in linkwatch_event 1 6 2499d 2645d 0/2 auto-closed as invalid on 2019/03/05 13:11
linux-5.15 INFO: task hung in linkwatch_event 1 84 251d 546d 0/3 auto-obsoleted due to no activity on 2025/01/11 00:55
upstream INFO: task hung in linkwatch_event (4) net 1 C done 3257 1d17h 349d 0/29 upstream: reported C repro on 2024/07/27 06:21
upstream INFO: task hung in linkwatch_event net 1 C 82 2092d 2703d 0/29 closed as dup on 2018/02/14 15:33
linux-4.14 INFO: task hung in linkwatch_event 1 5 1768d 1895d 0/1 auto-closed as invalid on 2021/01/05 01:42
linux-4.19 INFO: task hung in linkwatch_event (2) 1 C error 217 859d 1947d 0/1 upstream: reported C repro on 2020/03/11 20:12
upstream INFO: task hung in linkwatch_event (2) net 1 C done done 1033 1173d 1899d 20/29 fixed on 2022/05/13 11:13
linux-4.19 INFO: task hung in linkwatch_event 1 3 2101d 2215d 0/1 auto-closed as invalid on 2020/02/07 01:11
upstream INFO: task hung in linkwatch_event (3) net 1 1634 367d 961d 26/29 fixed on 2024/07/09 19:14
linux-4.14 INFO: task hung in linkwatch_event (3) 1 2 919d 919d 0/1 upstream: reported on 2023/01/03 10:49
android-49 INFO: task hung in linkwatch_event 1 13 2263d 2280d 0/3 auto-closed as invalid on 2019/10/25 08:50
linux-6.1 INFO: task hung in linkwatch_event (2) 1 32 302d 416d 0/3 auto-obsoleted due to no activity on 2024/11/21 00:32
linux-6.1 INFO: task hung in linkwatch_event 1 2 705d 821d 0/3 auto-obsoleted due to no activity on 2023/11/14 00:59
linux-6.1 INFO: task hung in linkwatch_event (3) 1 1 227d 227d 0/3 auto-obsoleted due to no activity on 2025/03/05 15:51

Sample crash report:
INFO: task kworker/u4:9:3478 blocked for more than 144 seconds.
      Not tainted 6.6.95-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u4:9    state:D stack:22320 pid:3478  ppid:2      flags:0x00004000
Workqueue: events_unbound linkwatch_event
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5381 [inline]
 __schedule+0x14e2/0x4580 kernel/sched/core.c:6700
 schedule+0xbd/0x170 kernel/sched/core.c:6774
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:6833
 __mutex_lock_common kernel/locking/mutex.c:679 [inline]
 __mutex_lock+0x6b7/0xcc0 kernel/locking/mutex.c:747
 linkwatch_event+0xe/0x60 net/core/link_watch.c:286
 process_one_work kernel/workqueue.c:2634 [inline]
 process_scheduled_works+0xa45/0x15b0 kernel/workqueue.c:2711

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/07/04 13:16 linux-6.6.y 3f5b4c104b7d 76ad128c .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: task hung in linkwatch_event
* Struck through repros no longer work on HEAD.