[v6.6] INFO: task hung in tun_chr_close

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 3b9f64db0496 Linux 6.6.138
git tree: linux-6.6.y
console output: https://syzkaller.appspot.com/x/log.txt?x=12dd1696580000
kernel config: https://syzkaller.appspot.com/x/.config?x=c5b35c4db8465904
dashboard link: https://syzkaller.appspot.com/bug?extid=9e8fe9504d557db8a499
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=13c79f6c580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=11ac7b26580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/191b79864499/disk-3b9f64db.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/7190b56a582e/vmlinux-3b9f64db.xz
kernel image: https://storage.googleapis.com/syzbot-assets/afa2fbf1faa4/bzImage-3b9f64db.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+9e8fe9...@syzkaller.appspotmail.com

INFO: task syz.0.19:5950 blocked for more than 142 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.19 state:D stack:25552 pid:5950 ppid:5904 flags:0x00004006
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5381 [inline]
__schedule+0x1553/0x45a0 kernel/sched/core.c:6700
schedule+0xbd/0x170 kernel/sched/core.c:6774
schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:6833
__mutex_lock_common kernel/locking/mutex.c:679 [inline]
__mutex_lock+0x6a9/0xcc0 kernel/locking/mutex.c:747
tun_detach drivers/net/tun.c:698 [inline]
tun_chr_close+0x41/0x1c0 drivers/net/tun.c:3511
__fput+0x234/0x970 fs/file_table.c:384
task_work_run+0x1d4/0x260 kernel/task_work.c:245


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