INFO: task syz-executor.0:6285 blocked for more than 143 seconds.
      Not tainted 6.3.0-rc7-syzkaller-00084-g14f8db1c0f9a #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor.0  state:D stack:0     pid:6285  ppid:1      flags:0x00000001
Call trace:
 __switch_to+0x320/0x754 arch/arm64/kernel/process.c:556
 context_switch kernel/sched/core.c:5307 [inline]
 __schedule+0x103c/0x1e2c kernel/sched/core.c:6625
 schedule+0xc4/0x170 kernel/sched/core.c:6701
 schedule_timeout+0xb8/0x348 kernel/time/timer.c:2143
 do_wait_for_common+0x30c/0x468 kernel/sched/completion.c:85
 __wait_for_common kernel/sched/completion.c:106 [inline]
 wait_for_common kernel/sched/completion.c:117 [inline]
 wait_for_completion+0x48/0x60 kernel/sched/completion.c:138
 __flush_workqueue+0x580/0x11c4 kernel/workqueue.c:2962
 drain_workqueue+0xb8/0x32c kernel/workqueue.c:3075
 destroy_workqueue+0xb4/0xa7c kernel/workqueue.c:4538
 btrfs_destroy_workqueue+0x48/0x2f0 fs/btrfs/async-thread.c:327
 btrfs_stop_all_workers+0x40/0x25c fs/btrfs/disk-io.c:1995
 close_ctree+0x558/0xdd8 fs/btrfs/disk-io.c:4633
 btrfs_put_super+0x40/0x50 fs/btrfs/super.c:82
 generic_shutdown_super+0x130/0x328 fs/super.c:500
 kill_anon_super+0x4c/0x74 fs/super.c:1107
 btrfs_kill_super+0x40/0x58 fs/btrfs/super.c:2133
 deactivate_locked_super+0xac/0x124 fs/super.c:331
 deactivate_super+0xe0/0x100 fs/super.c:362
 cleanup_mnt+0x34c/0x3dc fs/namespace.c:1177
 __cleanup_mnt+0x20/0x30 fs/namespace.c:1184
 task_work_run+0x230/0x2e0 kernel/task_work.c:179
 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
 do_notify_resume+0x2180/0x3c90 arch/arm64/kernel/signal.c:1304
 prepare_exit_to_user_mode arch/arm64/kernel/entry-common.c:137 [inline]
 exit_to_user_mode arch/arm64/kernel/entry-common.c:142 [inline]
 el0_svc+0x90/0x15c arch/arm64/kernel/entry-common.c:638
 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
 el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:591

Showing all locks held in the system:
1 lock held by rcu_tasks_kthre/12:
 #0: ffff800015f3f4d0 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x44/0xcf4 kernel/rcu/tasks.h:510
1 lock held by rcu_tasks_trace/13:
 #0: ffff800015f3fcd0 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x44/0xcf4 kernel/rcu/tasks.h:510
1 lock held by khungtaskd/28:
 #0: ffff800015f3f300 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0xc/0x44 include/linux/rcupdate.h:326
2 locks held by kworker/u4:4/1652:
 #0: ffff0000d8b74138 ((wq_completion)btrfs-fixup){+.+.}-{0:0}, at: process_one_work+0x664/0x12d4 kernel/workqueue.c:2363
 #1: ffff800022eb7c20 ((work_completion)(&work->normal_work)){+.+.}-{0:0}, at: process_one_work+0x6a8/0x12d4 kernel/workqueue.c:2365
2 locks held by getty/5685:
 #0: ffff0000d450e098 (&tty->ldisc_sem){++++}-{0:0}, at: ldsem_down_read+0x3c/0x4c drivers/tty/tty_ldsem.c:340
 #1: ffff80001ac902f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x414/0x1210 drivers/tty/n_tty.c:2177
1 lock held by syz-executor.0/6285:
 #0: ffff0000d1bd40e0 (&type->s_umount_key#49){+.+.}-{3:3}, at: deactivate_super+0xd8/0x100 fs/super.c:361

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