------------[ cut here ]------------
refcnt < 0
WARNING: net/bluetooth/hci_conn.c:649 at hci_conn_timeout+0x16a/0x230 net/bluetooth/hci_conn.c:649, CPU#2: kworker/u34:3/5784
Modules linked in:
CPU: 2 UID: 0 PID: 5784 Comm: kworker/u34:3 Tainted: G             L     Y syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP, [Y]=FORCED_BIND
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
Workqueue: hci2 hci_conn_timeout
RIP: 0010:hci_conn_timeout+0x16a/0x230 net/bluetooth/hci_conn.c:649
Code: 44 0f b6 2d 93 cc 85 07 31 ff 41 83 e5 40 44 89 ee e8 6a bf 2e f7 45 84 ed 0f 84 02 ff ff ff e9 e5 bb 93 f6 e8 47 c5 2e f7 90 <0f> 0b 90 e8 3e c5 2e f7 48 8d bb ed f5 ff ff 48 b8 00 00 00 00 00
RSP: 0018:ffffc90003137bf8 EFLAGS: 00010293
RAX: 0000000000000000 RBX: ffff888039020a50 RCX: 0000000000000000
RDX: ffff88802bfd0000 RSI: ffffffff8adf9b39 RDI: 0000000000000005
RBP: 00000000ffffffff R08: 0000000000000000 R09: 00000000ffffffff
R10: ffff888039020013 R11: 000000000000777b R12: ffff888039020000
R13: ffff88802bfd04c4 R14: 0000000000000000 R15: ffff88802b190c00
FS:  0000000000000000(0000) GS:ffff8880d468e000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fe9a0bf4158 CR3: 000000001e700000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 process_one_work+0xac7/0x1b10 kernel/workqueue.c:3495
 process_scheduled_works kernel/workqueue.c:3578 [inline]
 worker_thread+0x5ef/0xe50 kernel/workqueue.c:3659
 kthread+0x373/0x450 kernel/kthread.c:436
 ret_from_fork+0x730/0xd60 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>