syzbot

INFO: task kworker/0:19:4294 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/0:19    state:D
 stack:24040 pid: 4294 ppid:     2 flags:0x00004000
Workqueue: events_long flush_old_commits

Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11bb/0x4390 kernel/sched/core.c:6395
 schedule+0x11b/0x1e0 kernel/sched/core.c:6478
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6537
 __mutex_lock_common+0xc71/0x2390 kernel/locking/mutex.c:669
 __mutex_lock kernel/locking/mutex.c:729 [inline]
 mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
 reiserfs_write_lock+0x75/0xd0 fs/reiserfs/lock.c:27
 reiserfs_sync_fs fs/reiserfs/super.c:76 [inline]
 flush_old_commits+0x1de/0x2f0 fs/reiserfs/super.c:111
 process_one_work+0x863/0x1000 kernel/workqueue.c:2310
 worker_thread+0xaa8/0x12a0 kernel/workqueue.c:2457
 kthread+0x436/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>

Showing all locks held in the system:
4 locks held by kworker/1:1/23:
 #0: 
ffff888016871138
 ((wq_completion)events_long){+.+.}-{0:0}, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1
 #1: ffffc90000ddfd00 ((work_completion)(&(&sbi->old_work)->work)){+.+.}-{0:0}, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285
 #2: ffff888074c560e0 (&type->s_umount_key#53){.+.+}-{3:3}, at: flush_old_commits+0xc8/0x2f0 fs/reiserfs/super.c:97
 #3: ffff88807d0b4090 (&sbi->lock){+.+.}-{3:3}, at: reiserfs_write_lock+0x75/0xd0 fs/reiserfs/lock.c:27
1 lock held by khungtaskd/27:
 #0: ffffffff8c11c760 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30
2 locks held by getty/3949:
 #0: ffff88807f96b098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:252
 #1: 
ffffc900025e62e8
 (
&ldata->atomic_read_lock
){+.+.}-{3:3}, at: n_tty_read+0x5ba/0x1a30 drivers/tty/n_tty.c:2158
4 locks held by kworker/1:4/4223:
 #0: ffff888016871138 ((wq_completion)events_long){+.+.}-{0:0}, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1
 #1: ffffc90002f3fd00 ((work_completion)(&(&sbi->old_work)->work)){+.+.}-{0:0}, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285
 #2: ffff88807948c0e0 (&type->s_umount_key#53){.+.+}-{3:3}, at: flush_old_commits+0xc8/0x2f0 fs/reiserfs/super.c:97
 #3: ffff888142195090 (&sbi->lock){+.+.}-{3:3}, at: reiserfs_write_lock+0x75/0xd0 fs/reiserfs/lock.c:27
4 locks held by kworker/0:17/4292:
 #0: ffff888016871138 ((wq_completion)events_long){+.+.}-{0:0}, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1
 #1: ffffc900030ffd00 ((work_completion)(&(&sbi->old_work)->work)){+.+.}-{0:0}, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285
 #2: ffff88807963c0e0 (&type->s_umount_key#53){.+.+}-{3:3}, at: flush_old_commits+0xc8/0x2f0 fs/reiserfs/super.c:97
 #3: ffff88807e2f5090 (&sbi->lock){+.+.}-{3:3}, at: reiserfs_write_lock+0x75/0xd0 fs/reiserfs/lock.c:27
4 locks held by kworker/0:19/4294:
 #0: ffff888016871138 ((wq_completion)events_long){+.+.}-{0:0}, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1
 #1: 
ffffc9000312fd00
 (
(work_completion)(&(&sbi->old_work)->work)
){+.+.}-{0:0}
, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285
 #2: 
ffff8880773cc0e0
 (
&type->s_umount_key
#53
){.+.+}-{3:3}
, at: flush_old_commits+0xc8/0x2f0 fs/reiserfs/super.c:97
 #3: 
ffff888075a58090
 (
&sbi->lock
){+.+.}-{3:3}
, at: reiserfs_write_lock+0x75/0xd0 fs/reiserfs/lock.c:27
4 locks held by kworker/0:20/4295:
 #0: 
ffff888016871138
 (
(wq_completion)events_long
){+.+.}-{0:0}
, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1
 #1: 
ffffc9000313fd00
 (
(work_completion)(&(&sbi->old_work)->work)
){+.+.}-{0:0}
, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285
 #2: 
ffff88807af620e0
 (&type->s_umount_key#53){.+.+}-{3:3}, at: flush_old_commits+0xc8/0x2f0 fs/reiserfs/super.c:97
 #3: ffff88805c8e2090 (&sbi->lock){+.+.}-{3:3}, at: reiserfs_write_lock+0x75/0xd0 fs/reiserfs/lock.c:27
4 locks held by kworker/0:21/4296:
 #0: 
ffff888016871138
 (
(wq_completion)events_long
){+.+.}-{0:0}
, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1
 #1: ffffc9000314fd00 ((work_completion)(&(&sbi->old_work)->work)){+.+.}-{0:0}
, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285
 #2: 
ffff888025c600e0
 (
&type->s_umount_key
#53
){.+.+}-{3:3}
, at: flush_old_commits+0xc8/0x2f0 fs/reiserfs/super.c:97
 #3: 
ffff888078011090
 (
&sbi->lock
){+.+.}-{3:3}
, at: reiserfs_write_lock+0x75/0xd0 fs/reiserfs/lock.c:27
6 locks held by syz.0.17/4337:
3 locks held by syz.1.18/4365:
3 locks held by syz.2.19/4389:
3 locks held by syz.3.20/4412:
3 locks held by syz.4.21/4446:
3 locks held by syz.5.22/4478:
6 locks held by syz.6.23/4514:

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