INFO: task hung in udp_tunnel_nic_device_sync

INFO: task hung in udp_tunnel_nic_device_sync_work (2)

Status: closed as invalid on 2026/02/18 04:33
Subsystems: net
[Documentation on labels]
First crash: 105d, last: 105d

▶ ▼ Similar bugs (1)

Kernel	Title	Rank 🛈	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
upstream	INFO: task hung in udp_tunnel_nic_device_sync_work net	1	syz	error		7	219d	246d	0/29	closed as invalid on 2025/09/10 00:16

▶ ▼ Last patch testing requests (1)


Created	Duration	User	Patch	Repo	Result
2026/01/04 02:19	18m	retest repro		upstream	report log

Sample crash report:

INFO: task kworker/u4:5:119 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u4:5    state:D stack:19592 pid:119   tgid:119   ppid:2      task_flags:0x4208060 flags:0x00080000
Workqueue: udp_tunnel_nic udp_tunnel_nic_device_sync_work
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5256 [inline]
 __schedule+0x14bc/0x5000 kernel/sched/core.c:6863
 __schedule_loop kernel/sched/core.c:6945 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:6960
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7017
 __mutex_lock_common kernel/locking/mutex.c:692 [inline]
 __mutex_lock+0x7e6/0x1350 kernel/locking/mutex.c:776
 udp_tunnel_nic_device_sync_work+0x29/0xa10 net/ipv4/udp_tunnel_nic.c:736
 process_one_work kernel/workqueue.c:3257 [inline]
 process_scheduled_works+0xad1/0x1770 kernel/workqueue.c:3340
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3421
 kthread+0x711/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x599/0xb30 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
 </TASK>
INFO: task kworker/u4:13:1816 blocked for more than 153 seconds.

Crashes (1):
Time	Kernel	Commit	Syzkaller	Config	Log	Report	Syz repro	C repro	VM info	Assets (help?)	Manager	Title
2025/12/21 01:25	upstream	d8ba32c5a460	d1b870e1	.config	console log	report	syz / log			[disk image (non-bootable)] [vmlinux] [kernel image]	ci-snapshot-upstream-root	INFO: task hung in udp_tunnel_nic_device_sync_work

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