INFO: task hung in cangw_pernet_exit (2)

Status: upstream: reported on 2026/04/16 19:03
Reported-by: syzbot+f954b2c9821ea248f90f@syzkaller.appspotmail.com
First crash: 176d, last: 13d
▶ ▼ Similar bugs (6)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-4.19 INFO: task hung in cangw_pernet_exit 1 1 2274d 2274d 0/1 auto-closed as invalid on 2020/11/15 21:42
upstream INFO: task hung in cangw_pernet_exit net 1 14 2618d 3115d 0/29 closed as invalid on 2019/10/23 07:27
linux-4.19 INFO: task hung in cangw_pernet_exit (2) 1 6 1545d 1780d 0/1 auto-obsoleted due to no activity on 2022/11/15 03:06
upstream INFO: task hung in cangw_pernet_exit (2) can 1 85 2021d 2197d 0/29 auto-closed as invalid on 2021/06/26 13:07
upstream INFO: task hung in cangw_pernet_exit (3) can 1 syz unreliable 290 1747d 1853d 0/29 closed as invalid on 2022/02/08 10:22
linux-5.15 INFO: task hung in cangw_pernet_exit 1 27 828d 871d 0/3 auto-obsoleted due to no activity on 2024/09/11 11:31

Sample crash report:
INFO: task kworker/u4:0:9 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u4:0    state:D stack:18976 pid:    9 ppid:     2 flags:0x00004000
Workqueue: netns cleanup_net
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11c3/0x4350 kernel/sched/core.c:6395
 schedule+0x11b/0x1e0 kernel/sched/core.c:6478
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6537
 __mutex_lock_common+0xdf5/0x2400 kernel/locking/mutex.c:669
 __mutex_lock kernel/locking/mutex.c:729 [inline]
 mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
 cangw_pernet_exit+0xe/0x20 net/can/gw.c:1279
 ops_exit_list net/core/net_namespace.c:172 [inline]
 cleanup_net+0x703/0xba0 net/core/net_namespace.c:635
 process_one_work+0x867/0xff0 kernel/workqueue.c:2310
 worker_thread+0xad7/0x12a0 kernel/workqueue.c:2457
 kthread+0x42e/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>
INFO: task kworker/u4:3:436 blocked for more than 146 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u4:3    state:D stack:20384 pid:  436 ppid:     2 flags:0x00004000
Workqueue: events_unbound linkwatch_event
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11c3/0x4350 kernel/sched/core.c:6395
 schedule+0x11b/0x1e0 kernel/sched/core.c:6478
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6537
 __mutex_lock_common+0xdf5/0x2400 kernel/locking/mutex.c:669
 __mutex_lock kernel/locking/mutex.c:729 [inline]
 mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
 linkwatch_event+0xa/0x50 net/core/link_watch.c:251
 process_one_work+0x867/0xff0 kernel/workqueue.c:2310
 worker_thread+0xad7/0x12a0 kernel/workqueue.c:2457
 kthread+0x42e/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>
INFO: task syz-executor:4190 blocked for more than 147 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor    state:D stack:19472 pid: 4190 ppid:  4182 flags:0x00004002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11c3/0x4350 kernel/sched/core.c:6395
 schedule+0x11b/0x1e0 kernel/sched/core.c:6478
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6537
 __mutex_lock_common+0xdf5/0x2400 kernel/locking/mutex.c:669
 __mutex_lock kernel/locking/mutex.c:729 [inline]
 mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
 netdev_run_todo+0x8dd/0xac0 net/core/dev.c:10722
 tun_detach drivers/net/tun.c:705 [inline]
 tun_chr_close+0x13b/0x1b0 drivers/net/tun.c:3454
 __fput+0x212/0x8c0 fs/file_table.c:311
 task_work_run+0x125/0x1a0 kernel/task_work.c:188
 exit_task_work include/linux/task_work.h:33 [inline]
 do_exit+0x635/0x2110 kernel/exit.c:890
 do_group_exit+0x12c/0x2f0 kernel/exit.c:1004
 __do_sys_exit_group kernel/exit.c:1015 [inline]
 __se_sys_exit_group kernel/exit.c:1013 [inline]
 __x64_sys_exit_group+0x3b/0x40 kernel/exit.c:1013
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7faa9db5a159
RSP: 002b:00007fff84bfafe8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 00007faa9dbf052d RCX: 00007faa9db5a159
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000001
RBP: 0000000000000010 R08: 0000000000000000 R09: 00007faa9dbf04bb
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fff84bfc2a0
R13: 00007faa9dbf04bb R14: 000055557d9844e8 R15: 00007fff84bfd370
 </TASK>
INFO: task kworker/0:4:4231 blocked for more than 151 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/0:4     state:D stack:23600 pid: 4231 ppid:     2 flags:0x00004000
Workqueue: events_power_efficient crda_timeout_work
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11c3/0x4350 kernel/sched/core.c:6395
 schedule+0x11b/0x1e0 kernel/sched/core.c:6478
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6537
 __mutex_lock_common+0xdf5/0x2400 kernel/locking/mutex.c:669
 __mutex_lock kernel/locking/mutex.c:729 [inline]
 mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
 crda_timeout_work+0x11/0x50 net/wireless/reg.c:538
 process_one_work+0x867/0xff0 kernel/workqueue.c:2310
 worker_thread+0xad7/0x12a0 kernel/workqueue.c:2457
 kthread+0x42e/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287

Crashes (5):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/09/26 09:13 linux-5.15.y 0248c33e835e a3c7249d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in cangw_pernet_exit
2026/07/15 20:58 linux-5.15.y c86c4726e7f0 a4ed0f4f .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in cangw_pernet_exit
2026/07/07 10:24 linux-5.15.y c86c4726e7f0 8e71ce95 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in cangw_pernet_exit
2026/04/27 00:44 linux-5.15.y b9d57c40a767 9c2d0995 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in cangw_pernet_exit
2026/04/16 19:02 linux-5.15.y 91d48252ad4b 4743f87d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in cangw_pernet_exit
* Struck through repros no longer work on HEAD.