Re: [syzbot] [bluetooth?] WARNING in hci_connect_sco

From: syzbot

Date: Fri Oct 16 2026 - 11:55:29 EST


Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
WARNING in hci_connect_sco

------------[ cut here ]------------
workqueue: cannot queue hci_conn_timeout on wq hci4
WARNING: kernel/workqueue.c:2352 at __queue_work+0xdb7/0x1370 kernel/workqueue.c:2351, CPU#3: syz.3.10663/29395
Modules linked in:
CPU: 3 UID: 0 PID: 29395 Comm: syz.3.10663 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
RIP: 0010:__queue_work+0xdbb/0x1370 kernel/workqueue.c:2351
Code: 00 00 00 fc ff df 49 8d 94 24 70 01 00 00 48 89 f9 48 c1 e9 03 80 3c 01 00 0f 85 92 05 00 00 48 8d 3d f9 73 31 0f 48 8b 75 18 <67> 48 0f b9 3a 48 b8 00 00 00 00 00 fc ff df 48 89 ea 48 c1 ea 03
RSP: 0018:ffffc9000fb5fad0 EFLAGS: 00010046
RAX: dffffc0000000000 RBX: ffff888024bc4b00 RCX: 1ffff110068ce94d
RDX: ffff88802dd11170 RSI: ffffffff8aaa2470 RDI: ffffffff91015080
RBP: ffff888034674a50 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffff88802dd11000
R13: 1ffff92001f6bf64 R14: 0000000000000000 R15: ffff888034674a58
FS: 00007f7656c026c0(0000) GS:ffff8880d634f000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f7655c71fc0 CR3: 00000000333f3000 CR4: 0000000000352ef0
Call Trace:
<TASK>
__queue_delayed_work+0x357/0x450 kernel/workqueue.c:2617
queue_delayed_work_on+0x180/0x1e0 kernel/workqueue.c:2669
queue_delayed_work include/linux/workqueue.h:715 [inline]
hci_conn_drop include/net/bluetooth/hci_core.h:1729 [inline]
hci_conn_drop include/net/bluetooth/hci_core.h:1703 [inline]
hci_connect_sco+0x4d2/0xef0 net/bluetooth/hci_conn.c:1881
sco_connect net/bluetooth/sco.c:375 [inline]
sco_sock_connect+0x631/0x1800 net/bluetooth/sco.c:764
connect_socket net/socket.c:2141 [inline]
connect_socket net/socket.c:2131 [inline]
__sys_connect_file+0x146/0x1a0 net/socket.c:2166
__sys_connect+0x141/0x170 net/socket.c:2183
__do_sys_connect net/socket.c:2189 [inline]
__se_sys_connect net/socket.c:2186 [inline]
__x64_sys_connect+0x72/0xb0 net/socket.c:2186
do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
do_syscall_64+0x119/0x770 arch/x86/entry/syscall_64.c:84
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f7655d9c629
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f7656c02028 EFLAGS: 00000246 ORIG_RAX: 000000000000002a
RAX: ffffffffffffffda RBX: 00007f7656015fa0 RCX: 00007f7655d9c629
RDX: 0000000000000008 RSI: 0000200000000340 RDI: 0000000000000005
RBP: 00007f7655e32b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f7656016038 R14: 00007f7656015fa0 R15: 00007fffaa2a52b8
</TASK>
----------------
Code disassembly (best guess):
0: 00 00 add %al,(%rax)
2: 00 fc add %bh,%ah
4: ff lcall (bad)
5: df 49 8d fisttps -0x73(%rcx)
8: 94 xchg %eax,%esp
9: 24 70 and $0x70,%al
b: 01 00 add %eax,(%rax)
d: 00 48 89 add %cl,-0x77(%rax)
10: f9 stc
11: 48 c1 e9 03 shr $0x3,%rcx
15: 80 3c 01 00 cmpb $0x0,(%rcx,%rax,1)
19: 0f 85 92 05 00 00 jne 0x5b1
1f: 48 8d 3d f9 73 31 0f lea 0xf3173f9(%rip),%rdi # 0xf31741f
26: 48 8b 75 18 mov 0x18(%rbp),%rsi
* 2a: 67 48 0f b9 3a ud1 (%edx),%rdi <-- trapping instruction
2f: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax
36: fc ff df
39: 48 89 ea mov %rbp,%rdx
3c: 48 c1 ea 03 shr $0x3,%rdx


Tested on:

commit: 90201351 wifi: atk9k: Revert "wifi: ath9k: reject shor..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=13940305580000
kernel config: https://syzkaller.appspot.com/x/.config?x=1422747690f83bc1
dashboard link: https://syzkaller.appspot.com/bug?extid=5897b3c764f5989ea942
compiler: gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44

Note: no patches were applied.