Bluetooth: hci4 command 0x0406 tx timeout Bluetooth: hci0 command 0x0406 tx timeout Bluetooth: hci2 command 0x0406 tx timeout Bluetooth: hci1 command 0x0406 tx timeout Bluetooth: hci3 command 0x0406 tx timeout INFO: task syz-executor.1:8047 blocked for more than 140 seconds. Not tainted 4.14.213-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.1 D25768 8047 1 0x00000004 Call Trace: context_switch kernel/sched/core.c:2808 [inline] __schedule+0x88b/0x1de0 kernel/sched/core.c:3384 schedule+0x8d/0x1b0 kernel/sched/core.c:3428 wb_wait_for_completion fs/fs-writeback.c:222 [inline] wb_wait_for_completion+0x118/0x170 fs/fs-writeback.c:218 sync_inodes_sb+0x173/0x880 fs/fs-writeback.c:2471 __sync_filesystem fs/sync.c:34 [inline] sync_filesystem fs/sync.c:67 [inline] sync_filesystem+0x12f/0x230 fs/sync.c:48 generic_shutdown_super+0x70/0x370 fs/super.c:432 kill_block_super+0x95/0xe0 fs/super.c:1161 deactivate_locked_super+0x6c/0xd0 fs/super.c:319 deactivate_super+0x7f/0xa0 fs/super.c:350 cleanup_mnt+0x186/0x2c0 fs/namespace.c:1183 task_work_run+0x11f/0x190 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:191 [inline] exit_to_usermode_loop+0x1ad/0x200 arch/x86/entry/common.c:164 prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline] syscall_return_slowpath arch/x86/entry/common.c:270 [inline] do_syscall_64+0x4a3/0x640 arch/x86/entry/common.c:297 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x460c47 RSP: 002b:00007ffcbc913768 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000460c47 RDX: 00000000004033a8 RSI: 0000000000000002 RDI: 00007ffcbc913810 RBP: 0000000000039919 R08: 0000000000000000 R09: 000000000000000b R10: 0000000000000005 R11: 0000000000000246 R12: 00007ffcbc9148c0 R13: 000000000263ca60 R14: 0000000000000000 R15: 000000000003984c Showing all locks held in the system: 2 locks held by kworker/u4:2/34: #0: ("writeback"){+.+.}, at: [] process_one_work+0x6b0/0x14a0 kernel/workqueue.c:2087 #1: ((&(&wb->dwork)->work)){+.+.}, at: [] process_one_work+0x6e6/0x14a0 kernel/workqueue.c:2091 1 lock held by khungtaskd/1531: #0: (tasklist_lock){.+.+}, at: [] debug_show_all_locks+0x7c/0x21a kernel/locking/lockdep.c:4548 2 locks held by syz-executor.1/8047: #0: (&type->s_umount_key#88){+.+.}, at: [] deactivate_super+0x77/0xa0 fs/super.c:349 #1: (&bdi->wb_switch_rwsem){+.+.}, at: [] bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:338 [inline] #1: (&bdi->wb_switch_rwsem){+.+.}, at: [] sync_inodes_sb+0x156/0x880 fs/fs-writeback.c:2469 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1531 Comm: khungtaskd Not tainted 4.14.213-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x1b2/0x283 lib/dump_stack.c:58 nmi_cpu_backtrace.cold+0x57/0x93 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x13a/0x17f lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:140 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:195 [inline] watchdog+0x5b9/0xb40 kernel/hung_task.c:274 kthread+0x30d/0x420 kernel/kthread.c:232 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 skipped: idling at pc 0xffffffff8720a96e