[v5.15] INFO: task hung in ip_fib_net_exit

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: c61bd26ae81a Linux 5.15.160
git tree: linux-5.15.y
console output: https://syzkaller.appspot.com/x/log.txt?x=15c843fc980000
kernel config: https://syzkaller.appspot.com/x/.config?x=235f0e81ca937c17
dashboard link: https://syzkaller.appspot.com/bug?extid=793811b54ddda3c956b9
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/d61a97eef8b9/disk-c61bd26a.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/ab4908b4b59b/vmlinux-c61bd26a.xz
kernel image: https://storage.googleapis.com/syzbot-assets/d818fd46802b/bzImage-c61bd26a.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+793811...@syzkaller.appspotmail.com

INFO: task kworker/u4:1:144 blocked for more than 143 seconds.
Not tainted 5.15.160-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u4:1 state:D stack:20544 pid: 144 ppid: 2 flags:0x00004000
Workqueue: netns cleanup_net
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5030 [inline]
__schedule+0x12c4/0x45b0 kernel/sched/core.c:6376
schedule+0x11b/0x1f0 kernel/sched/core.c:6459
schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6518
__mutex_lock_common+0xe34/0x25a0 kernel/locking/mutex.c:669
__mutex_lock kernel/locking/mutex.c:729 [inline]
mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
ip_fib_net_exit+0x25/0x370 net/ipv4/fib_frontend.c:1559
ops_exit_list net/core/net_namespace.c:172 [inline]
cleanup_net+0x6ce/0xb60 net/core/net_namespace.c:599
process_one_work+0x8a1/0x10c0 kernel/workqueue.c:2310


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