------------[ cut here ]------------
refcount_t: underflow; use-after-free.
WARNING: CPU: 1 PID: 9079 at lib/refcount.c:28 refcount_warn_saturate+0x14a/0x210 lib/refcount.c:28
Modules linked in:
CPU: 1 UID: 0 PID: 9079 Comm: syz.4.840 Not tainted 6.13.0-rc6-syzkaller-00038-g09a0fa92e5b4 #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
RIP: 0010:refcount_warn_saturate+0x14a/0x210 lib/refcount.c:28
Code: ff 89 de e8 28 e3 f9 fc 84 db 0f 85 66 ff ff ff e8 7b e8 f9 fc c6 05 0a bc a7 0b 01 90 48 c7 c7 a0 99 d1 8b e8 37 1f ba fc 90 <0f> 0b 90 90 e9 43 ff ff ff e8 58 e8 f9 fc 0f b6 1d e5 bb a7 0b 31
RSP: 0018:ffffc9000554f6e8 EFLAGS: 00010282
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff815a5139
RDX: ffff88802b360000 RSI: ffffffff815a5146 RDI: 0000000000000001
RBP: ffff8880263d9478 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000004 R12: ffff888041e0f000
R13: ffff8880263d9478 R14: ffffffff85c50370 R15: dffffc0000000000
FS:  0000000000000000(0000) GS:ffff88806a700000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f1839cd0d58 CR3: 000000000df7e000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 __refcount_sub_and_test include/linux/refcount.h:275 [inline]
 __refcount_dec_and_test include/linux/refcount.h:307 [inline]
 refcount_dec_and_test include/linux/refcount.h:325 [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+0x140/0x2b0 lib/klist.c:249
 device_move+0x12d/0x10b0 drivers/base/core.c:4636
 hci_conn_del_sysfs+0x81/0x170 net/bluetooth/hci_sysfs.c:75
 hci_conn_cleanup net/bluetooth/hci_conn.c:174 [inline]
 hci_conn_del+0x54e/0xdb0 net/bluetooth/hci_conn.c:1164
 hci_conn_hash_flush+0x4bf/0x790 net/bluetooth/hci_conn.c:2699
 hci_dev_close_sync+0x603/0x11a0 net/bluetooth/hci_sync.c:5212
 hci_dev_do_close+0x2e/0x90 net/bluetooth/hci_core.c:482
 hci_unregister_dev+0x213/0x620 net/bluetooth/hci_core.c:2697
 vhci_release+0x79/0xf0 drivers/bluetooth/hci_vhci.c:664
 __fput+0x3f8/0xb60 fs/file_table.c:450
 task_work_run+0x14e/0x250 kernel/task_work.c:239
 exit_task_work include/linux/task_work.h:43 [inline]
 do_exit+0xad8/0x2d70 kernel/exit.c:938
 do_group_exit+0xd3/0x2a0 kernel/exit.c:1087
 get_signal+0x24ed/0x26c0 kernel/signal.c:3017
 arch_do_signal_or_restart+0x90/0x7e0 arch/x86/kernel/signal.c:337
 exit_to_user_mode_loop kernel/entry/common.c:111 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline]
 irqentry_exit_to_user_mode+0x13f/0x280 kernel/entry/common.c:231
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623
RIP: 0033:0x7f6d0d847717
Code: Unable to access opcode bytes at 0x7f6d0d8476ed.
RSP: 002b:00007f6d0e70a1a0 EFLAGS: 00010206
RAX: 0000000000000000 RBX: 000000000000000b RCX: 00007f6d0d985d29
RDX: 00007f6d0e70a1c0 RSI: 00007f6d0e70a2f0 RDI: 000000000000000b
RBP: 00007f6d0da01b08 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000
R13: 0000000000000001 R14: 00007f6d0db76080 R15: 00007fff9befe738
 </TASK>