[syzbot] [net?] INFO: task hung in mpls_net_exit (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 83a7eefedc9b Linux 6.10-rc3
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=14a2c82e980000
kernel config: https://syzkaller.appspot.com/x/.config?x=c79815c08cc14227
dashboard link: https://syzkaller.appspot.com/bug?extid=a8b8d28a9e1a02270f42
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/3e8762812d56/disk-83a7eefe.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/29ef4962890d/vmlinux-83a7eefe.xz
kernel image: https://storage.googleapis.com/syzbot-assets/1a5e4d91d135/bzImage-83a7eefe.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+a8b8d2...@syzkaller.appspotmail.com

INFO: task kworker/u8:11:2895 blocked for more than 144 seconds.
Not tainted 6.10.0-rc3-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u8:11 state:D stack:22712 pid:2895 tgid:2895 ppid:2 flags:0x00004000
Workqueue: netns cleanup_net
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5408 [inline]
__schedule+0x1796/0x49d0 kernel/sched/core.c:6745
__schedule_loop kernel/sched/core.c:6822 [inline]
schedule+0x14b/0x320 kernel/sched/core.c:6837
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6894
__mutex_lock_common kernel/locking/mutex.c:684 [inline]
__mutex_lock+0x6a4/0xd70 kernel/locking/mutex.c:752
mpls_net_exit+0x7d/0x2a0 net/mpls/af_mpls.c:2708
ops_exit_list net/core/net_namespace.c:173 [inline]
cleanup_net+0x802/0xcc0 net/core/net_namespace.c:640
process_one_work kernel/workqueue.c:3231 [inline]
process_scheduled_works+0xa2c/0x1830 kernel/workqueue.c:3312
worker_thread+0x86d/0xd70 kernel/workqueue.c:3393
kthread+0x2f0/0x390 kernel/kthread.c:389
ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
</TASK>
INFO: task kworker/0:3:5107 blocked for more than 144 seconds.
Not tainted 6.10.0-rc3-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/0:3 state:D stack:21912 pid:5107 tgid:5107 ppid:2 flags:0x00004000
Workqueue: events linkwatch_event
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5408 [inline]
__schedule+0x1796/0x49d0 kernel/sched/core.c:6745
__schedule_loop kernel/sched/core.c:6822 [inline]
schedule+0x14b/0x320 kernel/sched/core.c:6837
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6894
__mutex_lock_common kernel/locking/mutex.c:684 [inline]
__mutex_lock+0x6a4/0xd70 kernel/locking/mutex.c:752
linkwatch_event+0xe/0x60 net/core/link_watch.c:276
process_one_work kernel/workqueue.c:3231 [inline]
process_scheduled_works+0xa2c/0x1830 kernel/workqueue.c:3312
worker_thread+0x86d/0xd70 kernel/workqueue.c:3393
kthread+0x2f0/0x390 kernel/kthread.c:389
ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244


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[Tetsuo Handa]

#syz fix: net/sched: act_api: fix possible infinite loop in tcf_idr_check_alloc()