INFO: task syz-executor.3:8033 blocked for more than 140 seconds.
      Not tainted 4.14.305-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.3  D25072  8033      1 0x80000006
Call Trace:
 context_switch kernel/sched/core.c:2811 [inline]
 __schedule+0x88b/0x1de0 kernel/sched/core.c:3386
 schedule+0x8d/0x1b0 kernel/sched/core.c:3430
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:3488
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x669/0x1310 kernel/locking/mutex.c:893
 kobject_uevent_env+0x755/0xf30 lib/kobject_uevent.c:460
 device_del+0x642/0xa80 drivers/base/core.c:2097
 hci_conn_del_sysfs+0xca/0x160 net/bluetooth/hci_sysfs.c:81
 hci_conn_cleanup+0x216/0x500 net/bluetooth/hci_conn.c:128
 hci_conn_del+0x253/0x6f0 net/bluetooth/hci_conn.c:611
 hci_conn_hash_flush+0x19c/0x260 net/bluetooth/hci_conn.c:1394
 hci_dev_do_close+0x57d/0xd80 net/bluetooth/hci_core.c:1642
 hci_unregister_dev+0x143/0x420 net/bluetooth/hci_core.c:3210
 vhci_release+0x70/0xe0 drivers/bluetooth/hci_vhci.c:354
 __fput+0x25f/0x7a0 fs/file_table.c:210
 task_work_run+0x11f/0x190 kernel/task_work.c:113
 exit_task_work include/linux/task_work.h:22 [inline]
 do_exit+0xa44/0x2850 kernel/exit.c:915