INFO: task kworker/u4:1:12 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/u4:1 state:D stack:22120 pid:12 ppid:2 flags:0x00004000 Workqueue: writeback wb_workfn (flush-7:0) Call Trace: context_switch kernel/sched/core.c:5380 [inline] __schedule+0x14d2/0x44d0 kernel/sched/core.c:6699 schedule+0xbd/0x170 kernel/sched/core.c:6773 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:6832 __mutex_lock_common kernel/locking/mutex.c:679 [inline] __mutex_lock+0x6b7/0xcc0 kernel/locking/mutex.c:747 hfsplus_find_init+0x154/0x1d0 fs/hfsplus/bfind.c:28 hfsplus_cat_write_inode+0x1e7/0x7b0 fs/hfsplus/inode.c:593 write_inode fs/fs-writeback.c:1483 [inline] __writeback_single_inode+0x705/0xee0 fs/fs-writeback.c:1700 writeback_sb_inodes+0x77c/0xef0 fs/fs-writeback.c:1926 __writeback_inodes_wb+0x111/0x240 fs/fs-writeback.c:1997 wb_writeback+0x464/0xba0 fs/fs-writeback.c:2107 wb_check_background_flush fs/fs-writeback.c:2177 [inline] wb_do_writeback fs/fs-writeback.c:2265 [inline] wb_workfn+0xb32/0xe20 fs/fs-writeback.c:2292 process_one_work kernel/workqueue.c:2634 [inline] process_scheduled_works+0xa45/0x15b0 kernel/workqueue.c:2711 worker_thread+0xa55/0xfc0 kernel/workqueue.c:2792 kthread+0x2fa/0x390 kernel/kthread.c:388 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293 Showing all locks held in the system: 4 locks held by kworker/u4:1/12: #0: ffff88801a27ed38 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline] ffff88801a27ed38 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711 #1: ffffc90000117d00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline] #1: ffffc90000117d00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711 #2: ffff8880272820e0 (&type->s_umount_key#56){++++}-{3:3}, at: super_trylock_shared+0x20/0xf0 fs/super.c:607 #3: ffff88802c6ec0b0 ( &tree->tree_lock ){+.+.}-{3:3}, at: hfsplus_find_init+0x154/0x1d0 fs/hfsplus/bfind.c:28 1 lock held by khungtaskd/28: #0: ffffffff8cd2ff20 ( rcu_read_lock