------------[ cut here ]------------
refcount_t: underflow; use-after-free.
WARNING: CPU: 1 PID: 8546 at lib/refcount.c:28 refcount_warn_saturate+0x14a/0x210 lib/refcount.c:28
Modules linked in:
CPU: 1 UID: 0 PID: 8546 Comm: syz.3.769 Not tainted 6.14.0-syzkaller-07540-geff5f16bfd87 #0 PREEMPT(full) 
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 98 e2 ee fc 84 db 0f 85 66 ff ff ff e8 bb e7 ee fc c6 05 84 0a a0 0b 01 90 48 c7 c7 80 a5 f3 8b e8 27 7e ae fc 90 <0f> 0b 90 90 e9 43 ff ff ff e8 98 e7 ee fc 0f b6 1d 5f 0a a0 0b 31
RSP: 0018:ffffc9000dbb7738 EFLAGS: 00010286
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff817aee18
RDX: ffff8880524e2440 RSI: ffffffff817aee25 RDI: 0000000000000001
RBP: ffff8880271b0078 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffff8880286f6800
R13: ffff8880271b0078 R14: ffffffff85f66dc0 R15: ffffffff90672b80
FS:  0000000000000000(0000) GS:ffff8880d6b14000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f28976d7d60 CR3: 000000003fe00000 CR4: 0000000000352ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
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+0x13f/0x2e0 lib/klist.c:249
 device_move+0x12d/0x10d0 drivers/base/core.c:4592
 hci_conn_del_sysfs+0x81/0x180 net/bluetooth/hci_sysfs.c:75
 hci_conn_cleanup net/bluetooth/hci_conn.c:175 [inline]
 hci_conn_del+0x55f/0xdc0 net/bluetooth/hci_conn.c:1167
 hci_conn_hash_flush+0x186/0x260 net/bluetooth/hci_conn.c:2702
 hci_dev_close_sync+0x602/0x11d0 net/bluetooth/hci_sync.c:5225
 hci_dev_do_close+0x2e/0x90 net/bluetooth/hci_core.c:483
 hci_unregister_dev+0x213/0x620 net/bluetooth/hci_core.c:2678
 vhci_release+0x79/0xf0 drivers/bluetooth/hci_vhci.c:665
 __fput+0x3ff/0xb70 fs/file_table.c:465
 task_work_run+0x14d/0x240 kernel/task_work.c:227
 exit_task_work include/linux/task_work.h:40 [inline]
 do_exit+0xafe/0x2d90 kernel/exit.c:954
 do_group_exit+0xd3/0x2a0 kernel/exit.c:1103
 get_signal+0x2673/0x26d0 kernel/signal.c:3035
 arch_do_signal_or_restart+0x8f/0x7d0 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]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0x150/0x2a0 kernel/entry/common.c:218
 do_syscall_64+0xda/0x260 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fe079bbfa25
Code: Unable to access opcode bytes at 0x7fe079bbf9fb.
RSP: 002b:00007fe07a989f80 EFLAGS: 00000293 ORIG_RAX: 00000000000000e6
RAX: fffffffffffffdfc RBX: 00007fe079da5fa0 RCX: 00007fe079bbfa25
RDX: 00007fe07a989fc0 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007fe079c0e2a0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000000
R13: 0000000000000000 R14: 00007fe079da5fa0 R15: 00007ffd6e6c9bc8
 </TASK>