INFO: task kworker/u4:13:4615 blocked for more than 144 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/u4:13 state:D stack:0 pid:4615 ppid:2 flags:0x00000008 Workqueue: writeback wb_workfn (flush-7:4) Call trace: __switch_to+0x2f4/0x550 arch/arm64/kernel/process.c:555 context_switch kernel/sched/core.c:5245 [inline] __schedule+0xdd0/0x1b0c kernel/sched/core.c:6562 schedule+0xc4/0x170 kernel/sched/core.c:6638 schedule_preempt_disabled+0x18/0x2c kernel/sched/core.c:6697 __mutex_lock_common+0xafc/0x1f60 kernel/locking/mutex.c:679 __mutex_lock kernel/locking/mutex.c:747 [inline] mutex_lock_nested+0x38/0x44 kernel/locking/mutex.c:799 jfs_commit_inode+0x19c/0x498 fs/jfs/inode.c:108 jfs_write_inode+0x128/0x1f8 fs/jfs/inode.c:138 write_inode fs/fs-writeback.c:1470 [inline] __writeback_single_inode+0x5e0/0x1554 fs/fs-writeback.c:1687 writeback_sb_inodes+0x858/0x143c fs/fs-writeback.c:1913 __writeback_inodes_wb+0x110/0x394 fs/fs-writeback.c:1984 wb_writeback+0x428/0xfcc 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+0xb38/0xe18 fs/fs-writeback.c:2270 process_one_work+0x7f8/0x13a4 kernel/workqueue.c:2292 worker_thread+0x8c4/0xfec kernel/workqueue.c:2439 kthread+0x250/0x2d8 kernel/kthread.c:376 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:850 Showing all locks held in the system: 2 locks held by kworker/0:0/7: 1 lock held by rcu_tasks_kthre/12: #0: ffff8000153f7c30 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x40/0xbb4 kernel/rcu/tasks.h:517 1 lock held by rcu_tasks_trace/13: #0: ffff8000153f8450 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x40/0xbb4 kernel/rcu/tasks.h:517 1 lock held by khungtaskd/28: #0: ffff8000153f72c0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0xc/0x44 include/linux/rcupdate.h:349 2 locks held by getty/4080: #0: ffff0000d9168098 (&tty->ldisc_sem){++++}-{0:0}, at: ldsem_down_read+0x3c/0x4c drivers/tty/tty_ldsem.c:340 #1: ffff800020a0e2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x2ec/0xfa0 drivers/tty/n_tty.c:2198 1 lock held by udevd/4310: 1 lock held by udevd/4313: 2 locks held by kworker/0:5/4369: #0: ffff0000c0020938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x6b8/0x13a4 kernel/workqueue.c:2265 #1: ffff800021297c20 ((work_completion)(&m->mpeg_thread)){+.+.}-{0:0}, at: process_one_work+0x6fc/0x13a4 kernel/workqueue.c:2267 2 locks held by kworker/1:7/4377: #0: ffff0000c0021938 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x6b8/0x13a4 kernel/workqueue.c:2265 #1: ffff800021357c20 ((work_completion)(&rew->rew_work)){+.+.}-{0:0}, at: process_one_work+0x6fc/0x13a4 kernel/workqueue.c:2267 4 locks held by kworker/u4:13/4615: #0: ffff0000c2c10938 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x6b8/0x13a4 kernel/workqueue.c:2265 #1: ffff800021397c20 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x6fc/0x13a4 kernel/workqueue.c:2267 #2: ffff0000ff4a40e0 (&type->s_umount_key#56){++++}-{3:3}, at: trylock_super+0x24/0xf4 fs/super.c:415 #3: ffff0000e2a53008 (&jfs_ip->commit_mutex){+.+.}-{3:3}, at: jfs_commit_inode+0x19c/0x498 fs/jfs/inode.c:108 3 locks held by syz.1.461/6440: 4 locks held by syz.4.789/7664: 3 locks held by syz.2.1335/9651: #0: ffff0000db40d468 (&hdev->req_lock){+.+.}-{3:3}, at: hci_dev_do_close net/bluetooth/hci_core.c:526 [inline] #0: ffff0000db40d468 (&hdev->req_lock){+.+.}-{3:3}, at: hci_unregister_dev+0x20c/0x4c0 net/bluetooth/hci_core.c:2731 #1: ffff0000db40c428 (&hdev->lock){+.+.}-{3:3}, at: hci_dev_close_sync+0x3a8/0xee8 net/bluetooth/hci_sync.c:5233 #2: ffff8000179e47a8 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_disconn_cfm include/net/bluetooth/hci_core.h:1829 [inline] #2: ffff8000179e47a8 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_conn_hash_flush+0xb0/0x26c net/bluetooth/hci_conn.c:2504 2 locks held by syz.0.1729/11111: =============================================