------------[ cut here ]------------
refcount_t: underflow; use-after-free.
WARNING: CPU: 1 PID: 5840 at lib/refcount.c:28 refcount_warn_saturate+0x11a/0x1d0 lib/refcount.c:28
Modules linked in:
CPU: 1 UID: 0 PID: 5840 Comm: syz-executor Not tainted 6.15.0-rc5-syzkaller-01021-g0b28182c73a3 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:refcount_warn_saturate+0x11a/0x1d0 lib/refcount.c:28
Code: 20 89 c1 8b e8 57 a4 cb fc 90 0f 0b 90 90 eb d7 e8 fb 47 07 fd c6 05 58 a6 b0 0a 01 90 48 c7 c7 80 89 c1 8b e8 37 a4 cb fc 90 <0f> 0b 90 90 eb b7 e8 db 47 07 fd c6 05 35 a6 b0 0a 01 90 48 c7 c7
RSP: 0000:ffffc9000413f7d8 EFLAGS: 00010246
RAX: 7387bba3db554f00 RBX: 0000000000000003 RCX: ffff88802f341e00
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000002
RBP: 0000000000000000 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffffbfff1bba4b4 R12: ffff88802bc29000
R13: ffff888051453860 R14: ffff888051453878 R15: dffffc0000000000
FS:  0000000000000000(0000) GS:ffff8881261c0000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f24847f84c0 CR3: 0000000032bce000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
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:4618
 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+0x8f5/0xca0 net/bluetooth/hci_conn.c:1167
 hci_conn_hash_flush+0x191/0x230 net/bluetooth/hci_conn.c:2535
 hci_dev_close_sync+0xaef/0x1330 net/bluetooth/hci_sync.c:5225
 hci_dev_do_close net/bluetooth/hci_core.c:483 [inline]
 hci_unregister_dev+0x206/0x500 net/bluetooth/hci_core.c:2678
 vhci_release+0x80/0xd0 drivers/bluetooth/hci_vhci.c:665
 __fput+0x449/0xa70 fs/file_table.c:465
 task_work_run+0x1d1/0x260 kernel/task_work.c:227
 exit_task_work include/linux/task_work.h:40 [inline]
 do_exit+0x8d6/0x2550 kernel/exit.c:953
 do_group_exit+0x21c/0x2d0 kernel/exit.c:1102
 __do_sys_exit_group kernel/exit.c:1113 [inline]
 __se_sys_exit_group kernel/exit.c:1111 [inline]
 __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1111
 x64_sys_call+0x21ba/0x21c0 arch/x86/include/generated/asm/syscalls_64.h:232
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xf6/0x210 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f2b1e98e969
Code: Unable to access opcode bytes at 0x7f2b1e98e93f.
RSP: 002b:00007ffeb2e03098 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f2b1e98e969
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000043
RBP: 00007f2b1ea12053 R08: 00007ffeb2e00e36 R09: 00000000000927c0
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000020
R13: 00000000000927c0 R14: 0000000000029c45 R15: 00007ffeb2e03250
 </TASK>