------------[ cut here ]------------
refcnt < 0
WARNING: net/bluetooth/hci_conn.c:631 at hci_conn_timeout+0xff/0x2c0, CPU#0: kworker/u11:0/53
Modules linked in:
CPU: 0 UID: 0 PID: 53 Comm: kworker/u11:0 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Workqueue: hci1 hci_conn_timeout
RIP: 0010:hci_conn_timeout+0xff/0x2c0
Code: 48 89 df e8 c3 cc 09 00 eb 07 e8 4c ba 02 f7 b0 13 0f b6 f0 48 89 df 5b 41 5c 41 5e 41 5f 5d e9 b7 a0 fe ff e8 32 ba 02 f7 90 <0f> 0b 90 eb 8c 44 89 f9 80 e1 07 80 c1 03 38 c1 0f 8c 31 ff ff ff
RSP: 0018:ffffc90000bd7ad0 EFLAGS: 00010293
RAX: ffffffff8ac4485e RBX: ffff88811eaec000 RCX: ffff8881001d1dc0
RDX: 0000000000000000 RSI: 00000000ffffffff RDI: 0000000000000000
RBP: 00000000ffffffff R08: ffff88811eaec013 R09: 1ffff11023d5d802
R10: dffffc0000000000 R11: ffffed1023d5d803 R12: dffffc0000000000
R13: dffffc0000000000 R14: ffff88811eaeca40 R15: ffff88811eaec010
FS:  0000000000000000(0000) GS:ffff88818d954000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2f51eff8 CR3: 0000000172b1c000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 process_scheduled_works+0xa8e/0x14e0
 worker_thread+0xa47/0xfb0
 kthread+0x388/0x470
 ret_from_fork+0x514/0xb70
 ret_from_fork_asm+0x1a/0x30
 </TASK>
