syzbot


INFO: task hung in rescuer_thread (3)

Status: upstream: reported syz repro on 2026/02/09 00:19
Subsystems: kernel
[Documentation on labels]
Reported-by: syzbot+1d6360305e34d30ab396@syzkaller.appspotmail.com
First crash: 30d, last: 5d16h
Cause bisection: failed (error log, bisect log)
  
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [kernel?] INFO: task hung in rescuer_thread (3) 0 (1) 2026/02/09 00:19
Similar bugs (2)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: task hung in rescuer_thread kernel 1 19 347d 644d 0/29 auto-obsoleted due to no activity on 2025/05/29 04:51
upstream INFO: task hung in rescuer_thread (2) riscv 1 3 169d 191d 0/29 auto-obsoleted due to no activity on 2025/11/23 15:57

Sample crash report:
INFO: task kworker/R-wg-cr:5992 blocked for more than 149 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/R-wg-cr state:D stack:25984 pid:5992  tgid:5992  ppid:2      task_flags:0x4208060 flags:0x00080000
Workqueue:  0x0 (wg-crypt-wg1)
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5260 [inline]
 __schedule+0x14ea/0x5050 kernel/sched/core.c:6867
 __schedule_loop kernel/sched/core.c:6949 [inline]
 schedule+0x164/0x360 kernel/sched/core.c:6964
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7021
 __mutex_lock_common kernel/locking/mutex.c:692 [inline]
 __mutex_lock+0x7fe/0x1300 kernel/locking/mutex.c:776
 worker_detach_from_pool kernel/workqueue.c:2730 [inline]
 rescuer_thread+0x593/0x1390 kernel/workqueue.c:3560
 kthread+0x726/0x8b0 kernel/kthread.c:463
 ret_from_fork+0x51b/0xa40 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
 </TASK>

Showing all locks held in the system:
1 lock held by kworker/R-rcu_g/4:
 #0: ffffffff8e3f8c88 (wq_pool_attach_mutex){+.+.}-{4:4}, at: worker_detach_from_pool kernel/workqueue.c:2730 [inline]
 #0: ffffffff8e3f8c88 (wq_pool_attach_mutex){+.+.}-{4:4}, at: rescuer_thread+0x593/0x1390 kernel/workqueue.c:3560

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/02/05 00:01 net-next 9a9424c756fe ea10c935 .config console log report syz / log [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce INFO: task hung in rescuer_thread
2026/01/10 22:13 upstream b6151c4e60e5 d1b870e1 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto INFO: task hung in rescuer_thread
* Struck through repros no longer work on HEAD.