Bluetooth: hci4: command 0x0406 tx timeout
------------[ cut here ]------------
refcnt < 0
WARNING: net/bluetooth/hci_conn.c:634 at hci_conn_timeout+0x16a/0x230 net/bluetooth/hci_conn.c:634, CPU#3: kworker/u33:2/16539
Modules linked in:
CPU: 3 UID: 0 PID: 16539 Comm: kworker/u33:2 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
Workqueue: hci4 hci_conn_timeout
RIP: 0010:hci_conn_timeout+0x16a/0x230 net/bluetooth/hci_conn.c:634
Code: 44 0f b6 2d 9b 17 53 06 31 ff 41 83 e5 40 44 89 ee e8 6a 2e 88 f7 45 84 ed 0f 84 02 ff ff ff e9 86 66 f1 f6 e8 07 34 88 f7 90 <0f> 0b 90 e8 fe 33 88 f7 48 8d bb fd f5 ff ff 48 b8 00 00 00 00 00
RSP: 0018:ffffc900233d7c10 EFLAGS: 00010293
RAX: 0000000000000000 RBX: ffff88805c9aca40 RCX: ffffffff8a7fc73f
RDX: ffff88802480ca80 RSI: ffffffff8a7fc839 RDI: ffff88802480ca80
RBP: 00000000ffffffff R08: 0000000000000005 R09: 0000000000000000
R10: 00000000ffffffff R11: 0000000000000000 R12: ffff88805c9ac000
R13: 0000000000000000 R14: ffff88802480cf44 R15: ffff88802b2de800
FS:  0000000000000000(0000) GS:ffff88809748a000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000f5300008 CR3: 0000000023687000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 process_one_work+0xa0e/0x1980 kernel/workqueue.c:3314
 process_scheduled_works kernel/workqueue.c:3397 [inline]
 worker_thread+0x5ef/0xe50 kernel/workqueue.c:3478
 kthread+0x370/0x450 kernel/kthread.c:436
 ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>