------------[ cut here ]------------
refcount_t: underflow; use-after-free.
WARNING: CPU: 0 PID: 6533 at lib/refcount.c:28 refcount_warn_saturate+0x154/0x1f8 lib/refcount.c:28
Modules linked in:
CPU: 0 UID: 0 PID: 6533 Comm: syz-executor Not tainted syzkaller #0 PREEMPT 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/30/2025
pstate: 63400005 (nZCv daif +PAN -UAO +TCO +DIT -SSBS BTYPE=--)
pc : refcount_warn_saturate+0x154/0x1f8 lib/refcount.c:28
lr : refcount_warn_saturate+0x154/0x1f8 lib/refcount.c:28
sp : ffff8000a32475f0
x29: ffff8000a32475f0 x28: 1ffff0001257e1a4 x27: 1fffe0001a9cdce1
x26: 0000000000000000 x25: ffff0000dc29bd00 x24: dfff800000000000
x23: ffff700014648ed0 x22: ffff800084be7b80 x21: 0000000000000000
x20: ffff0000cedbcc78 x19: ffff800092e28000 x18: 00000000ffffffff
x17: ffff80009353a000 x16: ffff80008b021028 x15: 0000000000000001
x14: 1ffff00014648e2c x13: 0000000000000000 x12: 0000000000000000
x11: 0000000000000000 x10: 0000000000ff0100 x9 : 532fc92cca8c8800
x8 : 532fc92cca8c8800 x7 : ffff800080565b6c x6 : 0000000000000000
x5 : 0000000000000000 x4 : 0000000000000000 x3 : ffff8000807e08b4
x2 : 0000000000000002 x1 : 0000000100000001 x0 : 0000000000000000
Call trace:
 refcount_warn_saturate+0x154/0x1f8 lib/refcount.c:28 (P)
 __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+0x380/0x3ac lib/klist.c:206
 klist_put lib/klist.c:217 [inline]
 klist_del lib/klist.c:230 [inline]
 klist_remove+0x190/0x334 lib/klist.c:249
 device_move+0x16c/0x5b0 drivers/base/core.c:4615
 hci_conn_del_sysfs+0xb4/0x170 net/bluetooth/hci_sysfs.c:75
 hci_conn_cleanup net/bluetooth/hci_conn.c:173 [inline]
 hci_conn_del+0xa40/0xf3c net/bluetooth/hci_conn.c:1211
 hci_conn_hash_flush+0x17c/0x218 net/bluetooth/hci_conn.c:2600
 hci_dev_close_sync+0x89c/0x1154 net/bluetooth/hci_sync.c:5294
 hci_dev_do_close net/bluetooth/hci_core.c:501 [inline]
 hci_unregister_dev+0x204/0x4c0 net/bluetooth/hci_core.c:2715
 vhci_release+0x12c/0x17c drivers/bluetooth/hci_vhci.c:690
 __fput+0x340/0x75c fs/file_table.c:468
 ____fput+0x20/0x58 fs/file_table.c:496
 task_work_run+0x1dc/0x260 kernel/task_work.c:227
 exit_task_work include/linux/task_work.h:40 [inline]
 do_exit+0x524/0x1a14 kernel/exit.c:961
 do_group_exit+0x194/0x22c kernel/exit.c:1102
 __do_sys_exit_group kernel/exit.c:1113 [inline]
 __se_sys_exit_group kernel/exit.c:1111 [inline]
 pid_child_should_wake+0x0/0x1dc kernel/exit.c:1111
 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
 invoke_syscall+0x98/0x254 arch/arm64/kernel/syscall.c:49
 el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132
 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151
 el0_svc+0x5c/0x254 arch/arm64/kernel/entry-common.c:744
 el0t_64_sync_handler+0x84/0x12c arch/arm64/kernel/entry-common.c:763
 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:596
irq event stamp: 752164
hardirqs last  enabled at (752163): [<ffff80008b01fd5c>] irqentry_exit+0xd8/0x108 kernel/entry/common.c:214
hardirqs last disabled at (752164): [<ffff80008b01a1ac>] el1_brk64+0x20/0x54 arch/arm64/kernel/entry-common.c:434
softirqs last  enabled at (751890): [<ffff8000892cbee0>] spin_unlock_bh include/linux/spinlock.h:396 [inline]
softirqs last  enabled at (751890): [<ffff8000892cbee0>] release_sock+0x14c/0x1ac net/core/sock.c:3735
softirqs last disabled at (751888): [<ffff8000892cbdc8>] spin_lock_bh include/linux/spinlock.h:356 [inline]
softirqs last disabled at (751888): [<ffff8000892cbdc8>] release_sock+0x34/0x1ac net/core/sock.c:3724
---[ end trace 0000000000000000 ]---