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#1: syz.4.6290/29921
Modules linked in:
CPU: 1 UID: 0 PID: 29921 Comm: syz.4.6290 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:refcount_warn_saturate+0xb2/0x110 lib/refcount.c:28
Code: 14 62 76 0b 67 48 0f b9 3a eb 4a e8 e8 5d 1f fd 48 8d 3d 11 62 76 0b 67 48 0f b9 3a eb 37 e8 d5 5d 1f fd 48 8d 3d 0e 62 76 0b <67> 48 0f b9 3a eb 24 e8 c2 5d 1f fd 48 8d 3d 0b 62 76 0b 67 48 0f
RSP: 0018:ffffc9000b04f7b8 EFLAGS: 00010283
RAX: ffffffff84a4dcfb RBX: 0000000000000003 RCX: 0000000000080000
RDX: ffffc9000b531000 RSI: 00000000000554c1 RDI: ffffffff901b3f10
RBP: 0000000000000000 R08: ffff88802ef8bc80 R09: 0000000000000005
R10: 0000000000000004 R11: 0000000000000002 R12: ffff888057251400
R13: ffff888032c1b860 R14: ffff888032c1b878 R15: dffffc0000000000
FS:  00007fdeef51a6c0(0000) GS:ffff8881255b0000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000564106fe2950 CR3: 000000004cc1e000 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+0x1c9/0x340 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+0xc36/0x1230 net/bluetooth/hci_conn.c:1240
 hci_conn_hash_flush+0x191/0x260 net/bluetooth/hci_conn.c:2645
 hci_dev_close_sync+0x821/0x10e0 net/bluetooth/hci_sync.c:5358
 hci_dev_do_close+0x30/0xc0 net/bluetooth/hci_core.c:502
 hci_rfkill_set_block+0x1f4/0x290 net/bluetooth/hci_core.c:930
 rfkill_set_block+0x1d2/0x440 net/rfkill/core.c:346
 rfkill_fop_write+0x461/0x5a0 net/rfkill/core.c:1301
 vfs_write+0x29a/0xb90 fs/read_write.c:686
 ksys_write+0x150/0x270 fs/read_write.c:740
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fdeee59bf79
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fdeef51a028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007fdeee815fa0 RCX: 00007fdeee59bf79
RDX: 0000000000000008 RSI: 00002000000002c0 RDI: 0000000000000004
RBP: 00007fdeee6327e0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fdeee816038 R14: 00007fdeee815fa0 R15: 00007ffce31781b8
 </TASK>
----------------
Code disassembly (best guess):
   0:	14 62                	adc    $0x62,%al
   2:	76 0b                	jbe    0xf
   4:	67 48 0f b9 3a       	ud1    (%edx),%rdi
   9:	eb 4a                	jmp    0x55
   b:	e8 e8 5d 1f fd       	call   0xfd1f5df8
  10:	48 8d 3d 11 62 76 0b 	lea    0xb766211(%rip),%rdi        # 0xb766228
  17:	67 48 0f b9 3a       	ud1    (%edx),%rdi
  1c:	eb 37                	jmp    0x55
  1e:	e8 d5 5d 1f fd       	call   0xfd1f5df8
  23:	48 8d 3d 0e 62 76 0b 	lea    0xb76620e(%rip),%rdi        # 0xb766238
* 2a:	67 48 0f b9 3a       	ud1    (%edx),%rdi <-- trapping instruction
  2f:	eb 24                	jmp    0x55
  31:	e8 c2 5d 1f fd       	call   0xfd1f5df8
  36:	48 8d 3d 0b 62 76 0b 	lea    0xb76620b(%rip),%rdi        # 0xb766248
  3d:	67                   	addr32
  3e:	48                   	rex.W
  3f:	0f                   	.byte 0xf