Bluetooth: hci2: Injecting HCI hardware error event
Bluetooth: hci2: 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#3: kworker/u33:0/64
Modules linked in:
CPU: 3 UID: 0 PID: 64 Comm: kworker/u33:0 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: hci2 hci_error_reset
RIP: 0010:refcount_warn_saturate+0xc9/0x120 lib/refcount.c:28
Code: 5d e9 7b d0 13 fd e8 76 d0 13 fd 48 8d 3d ff 05 e8 0b 67 48 0f b9 3a 5b 5d e9 63 d0 13 fd e8 5e d0 13 fd 48 8d 3d f7 05 e8 0b <67> 48 0f b9 3a 5b 5d e9 4b d0 13 fd e8 46 d0 13 fd 48 8d 3d ef 05
RSP: 0018:ffffc90000a0f888 EFLAGS: 00010293
RAX: 0000000000000000 RBX: 0000000000000003 RCX: ffffffff84aa8cac
RDX: ffff8880209cc980 RSI: ffffffff84aa8d12 RDI: ffffffff90929310
RBP: ffff88804f36f078 R08: 0000000000000005 R09: 0000000000000004
R10: 0000000000000003 R11: ffff8880209cd4b0 R12: ffff88801369b800
R13: ffff88804f36f078 R14: ffffffff85e459c0 R15: ffffffff906c3860
FS:  0000000000000000(0000) GS:ffff8880979f9000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000577ab4c0 CR3: 00000000298ff000 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 d0 13 fd       	jmp    0xfd13d081
   6:	e8 76 d0 13 fd       	call   0xfd13d081
   b:	48 8d 3d ff 05 e8 0b 	lea    0xbe805ff(%rip),%rdi        # 0xbe80611
  12:	67 48 0f b9 3a       	ud1    (%edx),%rdi
  17:	5b                   	pop    %rbx
  18:	5d                   	pop    %rbp
  19:	e9 63 d0 13 fd       	jmp    0xfd13d081
  1e:	e8 5e d0 13 fd       	call   0xfd13d081
  23:	48 8d 3d f7 05 e8 0b 	lea    0xbe805f7(%rip),%rdi        # 0xbe80621
* 2a:	67 48 0f b9 3a       	ud1    (%edx),%rdi <-- trapping instruction
  2f:	5b                   	pop    %rbx
  30:	5d                   	pop    %rbp
  31:	e9 4b d0 13 fd       	jmp    0xfd13d081
  36:	e8 46 d0 13 fd       	call   0xfd13d081
  3b:	48                   	rex.W
  3c:	8d                   	.byte 0x8d
  3d:	3d                   	.byte 0x3d
  3e:	ef                   	out    %eax,(%dx)
  3f:	05                   	.byte 0x5