INFO: task kworker/u8:3:50 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u8:3    state:D
 stack:20256 pid:50    tgid:50    ppid:2      task_flags:0x4208060 flags:0x00080000
Workqueue: writeback wb_workfn
 (flush-7:0)

Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5298 [inline]
 __schedule+0x15dd/0x52d0 kernel/sched/core.c:6911
 __schedule_loop kernel/sched/core.c:6993 [inline]
 schedule+0x164/0x360 kernel/sched/core.c:7008
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7065
 __mutex_lock_common kernel/locking/mutex.c:692 [inline]
 __mutex_lock+0x7fe/0x1300 kernel/locking/mutex.c:776
 hfsplus_find_init+0x168/0x2d0 fs/hfsplus/bfind.c:28
 hfsplus_cat_write_inode+0x22b/0x8e0 fs/hfsplus/inode.c:650
 write_inode fs/fs-writeback.c:1582 [inline]
 __writeback_single_inode+0x75a/0x11a0 fs/fs-writeback.c:1825
 writeback_sb_inodes+0x992/0x1a20 fs/fs-writeback.c:2054
 __writeback_inodes_wb+0x111/0x240 fs/fs-writeback.c:2130
 wb_writeback+0x46a/0xb70 fs/fs-writeback.c:2241
 wb_check_old_data_flush fs/fs-writeback.c:2345 [inline]
 wb_do_writeback fs/fs-writeback.c:2398 [inline]
 wb_workfn+0xb4c/0xf50 fs/fs-writeback.c:2426
 process_one_work kernel/workqueue.c:3288 [inline]
 process_scheduled_works+0xb6e/0x18c0 kernel/workqueue.c:3371
 worker_thread+0xa53/0xfc0 kernel/workqueue.c:3452
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/32:
 #0: 
ffffffff8e75e5e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
ffffffff8e75e5e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline]
ffffffff8e75e5e0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
4 locks held by kworker/u8:2/37:
 #0: ffff88801febf148 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3263 [inline]
 #0: ffff88801febf148 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0xa52/0x18c0 kernel/workqueue.c:3371
 #1: ffffc90000ad7c40 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3264 [inline]
 #1: ffffc90000ad7c40 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa8d/0x18c0 kernel/workqueue.c:3371
 #2: ffff8880338ae0e0 (&type->s_umount_key#52){.+.+}-{4:4}, at: super_trylock_shared+0x20/0xf0 fs/super.c:565
 #3: ffff8880366d80b0 (
&tree->tree_lock
){+.+.}-{4:4}