Bluetooth: hci5: hardware error 0x00
------------[ cut here ]------------
refcount_t: underflow; use-after-free.
WARNING: lib/refcount.c:28 at refcount_warn_saturate+0xc9/0x120 lib/refcount.c:28, CPU#1: kworker/u33:4/5947
Modules linked in:
CPU: 1 UID: 0 PID: 5947 Comm: kworker/u33:4 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~bpo12+1 04/01/2014
Workqueue: hci5 hci_error_reset
RIP: 0010:refcount_warn_saturate+0xc9/0x120 lib/refcount.c:28
Code: 5d e9 7b 29 12 fd e8 76 29 12 fd 48 8d 3d ef 6f e5 0b 67 48 0f b9 3a 5b 5d e9 63 29 12 fd e8 5e 29 12 fd 48 8d 3d e7 6f e5 0b <67> 48 0f b9 3a 5b 5d e9 4b 29 12 fd e8 46 29 12 fd 48 8d 3d df 6f
RSP: 0018:ffffc90003dff888 EFLAGS: 00010293
RAX: 0000000000000000 RBX: 0000000000000003 RCX: ffffffff84acbefc
RDX: ffff888024de8000 RSI: ffffffff84acbf62 RDI: ffffffff90922f50
RBP: ffff88804ad78478 R08: 0000000000000005 R09: 0000000000000004
R10: 0000000000000003 R11: 0000000000002ba1 R12: ffff888021c51c00
R13: ffff88804ad78478 R14: ffffffff85e68110 R15: ffffffff906bfce0
FS:  0000000000000000(0000) GS:ffff8880d69f5000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f109d665f98 CR3: 0000000021e5b000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 __refcount_sub_and_test include/linux/refcount.h:400 [inline]
 __refcount_dec_and_test include/linux/refcount.h:432 [inline]
 refcount_dec_and_test include/linux/refcount.h:450 [inline]
 kref_put include/linux/kref.h:64 [inline]
 klist_dec_and_del lib/klist.c:206 [inline]
 klist_put+0x11b/0x1b0 lib/klist.c:217
 klist_del lib/klist.c:230 [inline]
 klist_remove+0x13f/0x2e0 lib/klist.c:249
 device_move+0x12d/0x1160 drivers/base/core.c:4615
 hci_conn_del_sysfs+0xaa/0x1a0 net/bluetooth/hci_sysfs.c:75
 hci_conn_cleanup net/bluetooth/hci_conn.c:173 [inline]
 hci_conn_del+0x680/0x11d0 net/bluetooth/hci_conn.c:1234
 hci_conn_hash_flush+0x186/0x290 net/bluetooth/hci_conn.c:2638
 hci_dev_close_sync+0x601/0x1260 net/bluetooth/hci_sync.c:5326
 hci_dev_do_close+0x2e/0xc0 net/bluetooth/hci_core.c:501
 hci_error_reset+0xbf/0x390 net/bluetooth/hci_core.c:1034
 process_one_work+0x9ba/0x1b20 kernel/workqueue.c:3257
 process_scheduled_works kernel/workqueue.c:3340 [inline]
 worker_thread+0x6c8/0xf10 kernel/workqueue.c:3421
 kthread+0x3c5/0x780 kernel/kthread.c:463
 ret_from_fork+0x983/0xb10 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
 </TASK>
----------------
Code disassembly (best guess):
   0:	5d                   	pop    %rbp
   1:	e9 7b 29 12 fd       	jmp    0xfd122981
   6:	e8 76 29 12 fd       	call   0xfd122981
   b:	48 8d 3d ef 6f e5 0b 	lea    0xbe56fef(%rip),%rdi        # 0xbe57001
  12:	67 48 0f b9 3a       	ud1    (%edx),%rdi
  17:	5b                   	pop    %rbx
  18:	5d                   	pop    %rbp
  19:	e9 63 29 12 fd       	jmp    0xfd122981
  1e:	e8 5e 29 12 fd       	call   0xfd122981
  23:	48 8d 3d e7 6f e5 0b 	lea    0xbe56fe7(%rip),%rdi        # 0xbe57011
* 2a:	67 48 0f b9 3a       	ud1    (%edx),%rdi <-- trapping instruction
  2f:	5b                   	pop    %rbx
  30:	5d                   	pop    %rbp
  31:	e9 4b 29 12 fd       	jmp    0xfd122981
  36:	e8 46 29 12 fd       	call   0xfd122981
  3b:	48                   	rex.W
  3c:	8d                   	.byte 0x8d
  3d:	3d                   	.byte 0x3d
  3e:	df                   	.byte 0xdf
  3f:	6f                   	outsl  %ds:(%rsi),(%dx)