------------[ cut here ]------------
refcount_t: underflow; use-after-free.
WARNING: CPU: 1 PID: 11491 at lib/refcount.c:28 refcount_warn_saturate+0x11a/0x1d0 lib/refcount.c:28
Modules linked in:
CPU: 1 UID: 0 PID: 11491 Comm: syz.3.1545 Not tainted 6.17.0-rc1-syzkaller-00108-g065c31f2c691 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:refcount_warn_saturate+0x11a/0x1d0 lib/refcount.c:28
Code: 40 af e2 8b e8 67 72 bb fc 90 0f 0b 90 90 eb d7 e8 bb d3 f7 fc c6 05 64 99 c5 0a 01 90 48 c7 c7 a0 af e2 8b e8 47 72 bb fc 90 <0f> 0b 90 90 eb b7 e8 9b d3 f7 fc c6 05 41 99 c5 0a 01 90 48 c7 c7
RSP: 0018:ffffc9000210f598 EFLAGS: 00010246
RAX: e9ba44ca52c4d000 RBX: 0000000000000003 RCX: ffff88802683da00
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000002
RBP: 0000000000000000 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffffbfff1bfa1ec R12: ffff88807ef58400
R13: ffff888056b3cc60 R14: ffff888056b3cc78 R15: dffffc0000000000
FS:  0000000000000000(0000) GS:ffff888125d1c000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f11f96d8e9c CR3: 000000000df36000 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+0x193/0x700 drivers/base/core.c:4615
 hci_conn_del_sysfs+0xb8/0x170 net/bluetooth/hci_sysfs.c:75
 hci_conn_cleanup net/bluetooth/hci_conn.c:175 [inline]
 hci_conn_del+0x949/0xcf0 net/bluetooth/hci_conn.c:1176
 hci_conn_hash_flush+0x191/0x230 net/bluetooth/hci_conn.c:2565
 hci_dev_close_sync+0xaef/0x1330 net/bluetooth/hci_sync.c:5294
 hci_dev_do_close net/bluetooth/hci_core.c:501 [inline]
 hci_unregister_dev+0x21a/0x510 net/bluetooth/hci_core.c:2715
 vhci_release+0x80/0xd0 drivers/bluetooth/hci_vhci.c:665
 __fput+0x449/0xa70 fs/file_table.c:468
 task_work_run+0x1d4/0x260 kernel/task_work.c:227
 exit_task_work include/linux/task_work.h:40 [inline]
 do_exit+0x6b5/0x2300 kernel/exit.c:961
 do_group_exit+0x21c/0x2d0 kernel/exit.c:1102
 get_signal+0x1286/0x1340 kernel/signal.c:3034
 arch_do_signal_or_restart+0x9a/0x750 arch/x86/kernel/signal.c:337
 exit_to_user_mode_loop+0x75/0x110 kernel/entry/common.c:40
 exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline]
 syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline]
 do_syscall_64+0x2bd/0x3b0 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fdd8af8ebe9
Code: Unable to access opcode bytes at 0x7fdd8af8ebbf.
RSP: 002b:00007ffd9e5a09b8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: ffffffffffffff92 RBX: 000000000005f51f RCX: 00007fdd8af8ebe9
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007fdd8b1b5fac
RBP: 0000000000000032 R08: 7fffffffffffffff R09: 0000000e9e5a0caf
R10: 00007ffd9e5a0ab0 R11: 0000000000000246 R12: 00007fdd8b1b5fac
R13: 00007ffd9e5a0ab0 R14: 000000000005f551 R15: 00007ffd9e5a0ad0
 </TASK>