INFO: task kworker/0:17:4874 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/0:17    state:D stack:27440 pid: 4874 ppid:     2 flags:0x00004000
Workqueue: events_long flush_old_commits
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11c3/0x4350 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+0xdf5/0x2400 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+0x1fb/0x310 fs/reiserfs/super.c:111
 process_one_work+0x867/0xff0 kernel/workqueue.c:2310
 worker_thread+0xad7/0x12a0 kernel/workqueue.c:2457
 kthread+0x42e/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/1:0/21:
 #0: ffff888016c71138 ((wq_completion)events_long){+.+.}-{0:0}, at: process_one_work+0x75c/0xff0 kernel/workqueue.c:-1
 #1: 
ffffc90000db7d00 ((work_completion)(&(&sbi->old_work)->work)){+.+.}-{0:0}, at: process_one_work+0x79e/0xff0 kernel/workqueue.c:2285
 #2: ffff88802c0bc0e0 (&type->s_umount_key#53){.+.+}-{3:3}, at: flush_old_commits+0xce/0x310 fs/reiserfs/super.c:97
 #3: ffff88805ca81090 (&sbi->lock){+.+.}-{3:3}, at: reiserfs_write_lock+0x75/0xd0 fs/reiserfs/lock.c:27
4 locks held by kworker/1:1/25:
 #0: ffff888016c71138 ((wq_completion)events_long){+.+.}-{0:0}, at: process_one_work+0x75c/0xff0 kernel/workqueue.c:-1
 #1: ffffc90000dffd00 ((work_completion)(&(&sbi->old_work)->work)){+.+.}-{0:0}, at: process_one_work+0x79e/0xff0 kernel/workqueue.c:2285
 #2: ffff88807a19a0e0
 (
&type->s_umount_key
#53
){.+.+}-{3:3}
, at: flush_old_commits+0xce/0x310 fs/reiserfs/super.c:97
 #3: ffff888068371090 (&sbi->lock){+.+.}-{3:3}, at: reiserfs_write_lock+0x75/0xd0 fs/reiserfs/lock.c:27
1 lock held by khungtaskd/27:
 #0: ffffffff8c31ef20 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30
2 locks held by getty/3952:
 #0: ffff88802c734098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:252
 #1: ffffc90002cf62e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x594/0x1a50 drivers/tty/n_tty.c:2158
2 locks held by kworker/u4:4/4260:
4 locks held by kworker/1:15/4271:
 #0: 
ffff888016c71138
 (
(wq_completion)events_long
){+.+.}-{0:0}
, at: process_one_work+0x75c/0xff0 kernel/workqueue.c:-1
 #1: 
ffffc9000302fd00
 (
(work_completion)(&(&sbi->old_work)->work)
){+.+.}-{0:0}
, at: process_one_work+0x79e/0xff0 kernel/workqueue.c:2285
 #2: 
ffff888078c000e0
 (&type->s_umount_key#53){.+.+}-{3:3}, at: flush_old_commits+0xce/0x310 fs/reiserfs/super.c:97
 #3: 
ffff88801fd7f090
 (
&sbi->lock){+.+.}-{3:3}, at: reiserfs_write_lock+0x75/0xd0 fs/reiserfs/lock.c:27
2 locks held by kworker/1:17/4273:
 #0: 
ffff888016c72138
 (
(wq_completion)rcu_gp
){+.+.}-{0:0}
, at: process_one_work+0x75c/0xff0 kernel/workqueue.c:-1
 #1: 
ffffc9000304fd00
 (
(work_completion)(&rew.rew_work)
){+.+.}-{0:0}
, at: process_one_work+0x79e/0xff0 kernel/workqueue.c:2285
3 locks held by kworker/1:19/4275:
 #0: 
ffff88802b6c7138
 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x75c/0xff0 kernel/workqueue.c:-1
 #1: ffffc9000306fd00 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work+0x79e/0xff0 kernel/workqueue.c:2285
 #2: 
ffffffff8d43c1c8
 (
rtnl_mutex
){+.+.}-{3:3}
, at: addrconf_dad_work+0xc4/0x1530 net/ipv6/addrconf.c:4113
4 locks held by kworker/1:21/4277:
 #0: 
ffff888016c71138
 (
(wq_completion)events_long
){+.+.}-{0:0}
, at: process_one_work+0x75c/0xff0 kernel/workqueue.c:-1
 #1: 
ffffc9000308fd00
 (
(work_completion)(&(&sbi->old_work)->work)
){+.+.}-{0:0}
, at: process_one_work+0x79e/0xff0 kernel/workqueue.c:2285
 #2: 
ffff88806160c0e0
 (&type->s_umount_key#53){.+.+}-{3:3}, at: flush_old_commits+0xce/0x310 fs/reiserfs/super.c:97
 #3: ffff888077db6090 (&sbi->lock){+.+.}-{3:3}, at: reiserfs_write_lock+0x75/0xd0 fs/reiserfs/lock.c:27
3 locks held by kworker/0:7/4316:
 #0: