------------[ cut here ]------------
refcount_t: underflow; use-after-free.
WARNING: CPU: 0 PID: 21153 at lib/refcount.c:28 refcount_warn_saturate+0x14a/0x210 lib/refcount.c:28
Modules linked in:
CPU: 0 UID: 0 PID: 21153 Comm: syz.3.12815 Not tainted 6.14.0-rc2-syzkaller-00346-gba643b6d8440 #0
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 08 71 f7 fc 84 db 0f 85 66 ff ff ff e8 5b 76 f7 fc c6 05 ef 92 88 0b 01 90 48 c7 c7 80 f0 d2 8b e8 37 b0 b7 fc 90 <0f> 0b 90 90 e9 43 ff ff ff e8 38 76 f7 fc 0f b6 1d ca 92 88 0b 31
RSP: 0018:ffffc90004e97ac8 EFLAGS: 00010286
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffc90031b18000
RDX: 0000000000080000 RSI: ffffffff817a1236 RDI: 0000000000000001
RBP: ffff88806a5878fc R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000002 R12: ffff88806a5878fc
R13: ffff88806a587808 R14: 0000000000000000 R15: ffff88802b1292c0
FS: 0000000000000000(0000) GS:ffff88802b400000(0063) knlGS:00000000f5064b40
CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033
CR2: 0000000031cf2ffc CR3: 000000005e816000 CR4: 0000000000352ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 00000000000f0102 DR6: 00000000ffff0ff0 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]
sco_conn_put+0x2ea/0x4c0 net/bluetooth/sco.c:107
sco_chan_del+0x9c/0x1b0 net/bluetooth/sco.c:236
__sco_sock_close+0xab/0x210 net/bluetooth/sco.c:511
sco_sock_close net/bluetooth/sco.c:526 [inline]
sco_sock_release+0x6f/0x2d0 net/bluetooth/sco.c:1300
__sock_release+0xb0/0x270 net/socket.c:647
sock_close+0x1c/0x30 net/socket.c:1398
__fput+0x3ff/0xb70 fs/file_table.c:464
task_work_run+0x14e/0x250 kernel/task_work.c:227
get_signal+0x1d3/0x26c0 kernel/signal.c:2809
arch_do_signal_or_restart+0x90/0x7e0 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_fast_syscall_32+0x80/0x120 arch/x86/entry/common.c:389
do_fast_syscall_32+0x32/0x80 arch/x86/entry/common.c:411
entry_SYSENTER_compat_after_hwframe+0x84/0x8e
RIP: 0023:0xf7f83579
Code: b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 00 00 00 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 8d b4 26 00 00 00 00 8d b4 26 00 00 00 00
RSP: 002b:00000000f506455c EFLAGS: 00000296 ORIG_RAX: 000000000000016a
RAX: fffffffffffffffc RBX: 000000000000000a RCX: 0000000080000040
RDX: 0000000000000008 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000296 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
</TASK>
----------------
Code disassembly (best guess), 2 bytes skipped:
0: 10 06 adc %al,(%rsi)
2: 03 74 b4 01 add 0x1(%rsp,%rsi,4),%esi
6: 10 07 adc %al,(%rdi)
8: 03 74 b0 01 add 0x1(%rax,%rsi,4),%esi
c: 10 08 adc %cl,(%rax)
e: 03 74 d8 01 add 0x1(%rax,%rbx,8),%esi
1e: 00 51 52 add %dl,0x52(%rcx)
21: 55 push %rbp
22: 89 e5 mov %esp,%ebp
24: 0f 34 sysenter
26: cd 80 int $0x80
* 28: 5d pop %rbp <-- trapping instruction
29: 5a pop %rdx
2a: 59 pop %rcx
2b: c3 ret
2c: 90 nop
2d: 90 nop
2e: 90 nop
2f: 90 nop
30: 8d b4 26 00 00 00 00 lea 0x0(%rsi,%riz,1),%esi
37: 8d b4 26 00 00 00 00 lea 0x0(%rsi,%riz,1),%esi