INFO: task syz.3.423:7481 blocked for more than 149 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.3.423       state:D stack:24616 pid:7481  tgid:7481  ppid:5622   task_flags:0x400040 flags:0x00080002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5533 [inline]
 __schedule+0x17db/0x58f0 kernel/sched/core.c:7284
 __schedule_loop kernel/sched/core.c:7361 [inline]
 schedule+0x164/0x2b0 kernel/sched/core.c:7376
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7433
 __mutex_lock_common kernel/locking/mutex.c:726 [inline]
 __mutex_lock+0x7c1/0x1550 kernel/locking/mutex.c:821
 tun_detach drivers/net/tun.c:650 [inline]
 tun_chr_close+0x3e/0x1c0 drivers/net/tun.c:3592
 __fput+0x40d/0xa50 fs/file_table.c:512
 task_work_run+0x1d9/0x270 kernel/task_work.c:233
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 __exit_to_user_mode_loop kernel/entry/common.c:70 [inline]
 exit_to_user_mode_loop+0x204/0x770 kernel/entry/common.c:101
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:343 [inline]
 do_syscall_64+0x328/0x520 arch/x86/entry/syscall_64.c:89
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f38ce39e559
RSP: 002b:00007fff2391d528 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 00007f38ce627da0 RCX: 00007f38ce39e559
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 00007f38ce627da0 R08: 0000000000000006 R09: 0000000000000000
R10: 00007f38ce627cb0 R11: 0000000000000246 R12: 0000000000022928
R13: 00007f38ce62627c R14: 000000000002267b R15: 00007fff2391d630
 </TASK>

Showing all locks held in the system:
locks held by kthreadd/2: 1, last CPU#1:
 #0: ffffffff8feac5b0 (remove_cache_srcu){.+.+}-{0:0}, at: srcu_lock_acquire include/linux/srcu.h:198 [inline]
 #0: ffffffff8feac5b0 (remove_cache_srcu){.+.+}-{0:0}, at: srcu_read_lock+0x27/0x60 include/linux/srcu.h:305
locks held by kworker/0:0/9: 3, last CPU#0:
 #0: ffff88805930b140 ((wq_completion)wg-kex-wg1#8){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 #0: ffff88805930b140 ((wq_completion)wg-kex-wg1#8){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #0: ffff88805930b140 ((wq_completion)wg-kex-wg1#8){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3361 [inline]
 #0: ffff88805930b140 ((wq_completion)wg-kex-wg1#8){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3479