------------[ cut here ]------------
refcount_t: addition on 0; use-after-free.
WARNING: CPU: 1 PID: 8935 at lib/refcount.c:25 refcount_warn_saturate+0x169/0x1e0 lib/refcount.c:25
Modules linked in:
CPU: 0 PID: 8935 Comm: syz-executor.5 Not tainted 5.14.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:refcount_warn_saturate+0x169/0x1e0 lib/refcount.c:25
Code: 09 31 ff 89 de e8 f7 c8 9c fd 84 db 0f 85 36 ff ff ff e8 aa c2 9c fd 48 c7 c7 40 dc e3 89 c6 05 a4 aa 80 09 01 e8 14 b2 18 05 <0f> 0b e9 17 ff ff ff e8 8b c2 9c fd 0f b6 1d 89 aa 80 09 31 ff 89
RSP: 0018:ffffc9000226fb70 EFLAGS: 00010286
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: ffff88807c7a8000 RSI: ffffffff815dbd58 RDI: fffff5200044df60
RBP: 0000000000000002 R08: 0000000000000000 R09: 0000000000000000
R10: ffffffff815d5afe R11: 0000000000000000 R12: ffff88807b886a00
R13: 0000000000000067 R14: ffff888046b4e968 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b33725000 CR3: 00000000888f8000 CR4: 00000000001506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 __refcount_add include/linux/refcount.h:199 [inline]
 __refcount_inc include/linux/refcount.h:250 [inline]
 refcount_inc include/linux/refcount.h:267 [inline]
 sock_hold include/net/sock.h:702 [inline]
 sco_conn_del+0x279/0x2b0 net/bluetooth/sco.c:193
 sco_disconn_cfm+0x71/0xb0 net/bluetooth/sco.c:1205
 hci_disconn_cfm include/net/bluetooth/hci_core.h:1518 [inline]
 hci_conn_hash_flush+0x127/0x260 net/bluetooth/hci_conn.c:1608
 hci_dev_do_close+0x57d/0x1130 net/bluetooth/hci_core.c:1793
 hci_unregister_dev+0x1c0/0x5a0 net/bluetooth/hci_core.c:4029
 vhci_release+0x70/0xe0 drivers/bluetooth/hci_vhci.c:340
 __fput+0x288/0x9f0 fs/file_table.c:280
 task_work_run+0xdd/0x1a0 kernel/task_work.c:164
 exit_task_work include/linux/task_work.h:32 [inline]
 do_exit+0xbae/0x2a30 kernel/exit.c:825
 do_group_exit+0x125/0x310 kernel/exit.c:922
 __do_sys_exit_group kernel/exit.c:933 [inline]
 __se_sys_exit_group kernel/exit.c:931 [inline]
 __x64_sys_exit_group+0x3a/0x50 kernel/exit.c:931
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x4665f9
Code: Unable to access opcode bytes at RIP 0x4665cf.
RSP: 002b:00007fff028c02f8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 00007fff028c04b0 RCX: 00000000004665f9
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000043
RBP: 0000000000000000 R08: 0000000000000025 R09: 00007fff028c04b0
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000004bfc95
R13: 000000000000001c R14: 00000000ffffffff R15: 00007fff028c04f0