INFO: task kworker/u4:0:9 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u4:0    state:D stack:24320 pid:9     ppid:2      flags:0x00004000
Workqueue: writeback wb_workfn (flush-7:0)
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5244 [inline]
 __schedule+0x10ec/0x40b0 kernel/sched/core.c:6561
 schedule+0xb9/0x180 kernel/sched/core.c:6637
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6696
 __mutex_lock_common kernel/locking/mutex.c:679 [inline]
 __mutex_lock+0x555/0xaf0 kernel/locking/mutex.c:747
 hfsplus_find_init+0x150/0x1c0 fs/hfsplus/bfind.c:28
 hfsplus_cat_write_inode+0x1e3/0x820 fs/hfsplus/inode.c:590
 write_inode fs/fs-writeback.c:1470 [inline]
 __writeback_single_inode+0x75b/0x1160 fs/fs-writeback.c:1687
 writeback_sb_inodes+0xad8/0x17d0 fs/fs-writeback.c:1913
 __writeback_inodes_wb+0x12a/0x3f0 fs/fs-writeback.c:1984
 wb_writeback+0x47a/0xd00 fs/fs-writeback.c:2089
 wb_check_background_flush fs/fs-writeback.c:2155 [inline]
 wb_do_writeback fs/fs-writeback.c:2243 [inline]
 wb_workfn+0xbdd/0xec0 fs/fs-writeback.c:2270
 process_one_work+0x898/0x1160 kernel/workqueue.c:2292
 worker_thread+0xaa2/0x1250 kernel/workqueue.c:2439
 kthread+0x29d/0x330 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>

Showing all locks held in the system:
4 locks held by kworker/u4:0/9:
 #0: 
ffff88801aabe138
 (
(wq_completion)writeback
){+.+.}-{0:0}
, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267
 #1: 
ffffc900000e7d00
 (
(work_completion)(&(&wb->dwork)->work)
){+.+.}-{0:0}
, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267
 #2: 
ffff888019ebc0e0
 (
&type->s_umount_key
#53
){.+.+}-{3:3}
, at: trylock_super+0x1c/0xf0 fs/super.c:415
 #3: ffff8880783e20b0
 (&tree->tree_lock){+.+.}-{3:3}, at: hfsplus_find_init+0x150/0x1c0 fs/hfsplus/bfind.c:28
4 locks held by kworker/u4:1/11:
 #0: ffff88801aabe138 ((wq_completion)writeback
){+.+.}-{0:0}
, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267
 #1: 
ffffc90000107d00