Bluetooth: hci1: Opcode 0x0c1a failed: -4
Bluetooth: hci1: Error when powering off device on rfkill (-4)
------------[ cut here ]------------
refcount_t: underflow; use-after-free.
WARNING: lib/refcount.c:28 at refcount_warn_saturate+0xb2/0x110 lib/refcount.c:28, CPU#0: syz.1.4749/22281
Modules linked in:
CPU: 0 UID: 0 PID: 22281 Comm: syz.1.4749 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:refcount_warn_saturate+0xb2/0x110 lib/refcount.c:28
Code: d4 91 fe 0a 67 48 0f b9 3a eb 4a e8 c8 0c 33 fd 48 8d 3d d1 91 fe 0a 67 48 0f b9 3a eb 37 e8 b5 0c 33 fd 48 8d 3d ce 91 fe 0a <67> 48 0f b9 3a eb 24 e8 a2 0c 33 fd 48 8d 3d cb 91 fe 0a 67 48 0f
RSP: 0018:ffffc9000f1f77b8 EFLAGS: 00010287
RAX: ffffffff848deb0b RBX: 0000000000000003 RCX: 0000000000080000
RDX: ffffc9001b961000 RSI: 00000000000690ae RDI: ffffffff8f8c7ce0
RBP: 0000000000000000 R08: ffff8880267d9e80 R09: 0000000000000005
R10: 0000000000000004 R11: 0000000000000002 R12: ffff888058522400
R13: ffff888058a89860 R14: ffff888058a89878 R15: dffffc0000000000
FS:  00007fdfc2a786c0(0000) GS:ffff888125e21000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fe2843156c0 CR3: 00000000849a0000 CR4: 00000000003526f0
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+0x3c7/0x3d0 lib/klist.c:206
 klist_put lib/klist.c:217 [inline]
 klist_del lib/klist.c:230 [inline]
 klist_remove+0x1bd/0x340 lib/klist.c:249
 device_move+0x193/0x730 drivers/base/core.c:4615
 hci_conn_del_sysfs+0xb8/0x1a0 net/bluetooth/hci_sysfs.c:75
 hci_conn_cleanup net/bluetooth/hci_conn.c:173 [inline]
 hci_conn_del+0xc36/0x1240 net/bluetooth/hci_conn.c:1234
 hci_conn_hash_flush+0x191/0x260 net/bluetooth/hci_conn.c:2638
 hci_dev_close_sync+0x821/0x1100 net/bluetooth/hci_sync.c:5326
 hci_dev_do_close+0x30/0xc0 net/bluetooth/hci_core.c:501
 hci_rfkill_set_block+0x21d/0x330 net/bluetooth/hci_core.c:929
 rfkill_set_block+0x1d2/0x440 net/rfkill/core.c:346
 rfkill_fop_write+0x44b/0x570 net/rfkill/core.c:1301
 vfs_write+0x27e/0xb30 fs/read_write.c:684
 ksys_write+0x145/0x250 fs/read_write.c:738
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fdfc1b8f749
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fdfc2a78038 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007fdfc1de5fa0 RCX: 00007fdfc1b8f749
RDX: 0000000000000008 RSI: 0000200000000080 RDI: 0000000000000006
RBP: 00007fdfc1c13f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fdfc1de6038 R14: 00007fdfc1de5fa0 R15: 00007ffe08c6ded8
 </TASK>
----------------
Code disassembly (best guess), 1 bytes skipped:
   0:	91                   	xchg   %eax,%ecx
   1:	fe 0a                	decb   (%rdx)
   3:	67 48 0f b9 3a       	ud1    (%edx),%rdi
   8:	eb 4a                	jmp    0x54
   a:	e8 c8 0c 33 fd       	call   0xfd330cd7
   f:	48 8d 3d d1 91 fe 0a 	lea    0xafe91d1(%rip),%rdi        # 0xafe91e7
  16:	67 48 0f b9 3a       	ud1    (%edx),%rdi
  1b:	eb 37                	jmp    0x54
  1d:	e8 b5 0c 33 fd       	call   0xfd330cd7
  22:	48 8d 3d ce 91 fe 0a 	lea    0xafe91ce(%rip),%rdi        # 0xafe91f7
* 29:	67 48 0f b9 3a       	ud1    (%edx),%rdi <-- trapping instruction
  2e:	eb 24                	jmp    0x54
  30:	e8 a2 0c 33 fd       	call   0xfd330cd7
  35:	48 8d 3d cb 91 fe 0a 	lea    0xafe91cb(%rip),%rdi        # 0xafe9207
  3c:	67                   	addr32
  3d:	48                   	rex.W
  3e:	0f                   	.byte 0xf