syzbot
WARNING in l2cap_conn_start
Status:
upstream: reported on 2026/03/12 02:14
Subsystems:
bluetooth
Labels:
prio:low
[Documentation on labels]
Reported-by: syzbot+5a3ffe8f0bd0f1dead8e@syzkaller.appspotmail.com
First crash: 154d, last: 11d
Sample crash report:
------------[ cut here ]------------
workqueue: cannot queue hci_tx_work on wq hci0
WARNING: kernel/workqueue.c:2306 at __queue_work+0xd4a/0x10a0 kernel/workqueue.c:2305, CPU#0: kworker/0:1/10
Modules linked in:
CPU: 0 UID: 0 PID: 10 Comm: kworker/0:1 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
Workqueue: events l2cap_info_timeout
RIP: 0010:__queue_work+0xd66/0x10a0 kernel/workqueue.c:2305
Code: 49 81 c7 70 01 00 00 4c 8d 35 d6 00 cd 0e 48 89 f8 48 c1 e8 03 80 3c 18 00 74 05 e8 a4 6c a8 00 49 8b 75 18 4c 89 f7 4c 89 fa <67> 48 0f b9 3a 4c 89 e8 48 c1 e8 03 80 3c 18 00 74 08 4c 89 ef e8
RSP: 0018:ffffc9000023f830 EFLAGS: 00010046
RAX: 1ffff1100240098a RBX: dffffc0000000000 RCX: ffff88801bf0a540
RDX: ffff88803fe92970 RSI: ffffffff8ac51380 RDI: ffffffff905aeb30
RBP: 0000000000000020 R08: ffff888012004c3f R09: 1ffff11002400987
R10: dffffc0000000000 R11: ffffed1002400988 R12: 0000000000000008
R13: ffff888012004c38 R14: ffffffff905aeb30 R15: ffff88803fe92970
FS: 0000000000000000(0000) GS:ffff88808c53f000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f7e31351fb3 CR3: 0000000043827000 CR4: 0000000000352ef0
Call Trace:
<TASK>
queue_work_on+0x106/0x1d0 kernel/workqueue.c:2452
l2cap_conn_start+0x5e2/0xf70 net/bluetooth/l2cap_core.c:1604
l2cap_info_timeout+0x68/0xa0 net/bluetooth/l2cap_core.c:1714
process_one_work kernel/workqueue.c:3322 [inline]
process_scheduled_works+0xa8e/0x14e0 kernel/workqueue.c:3405
worker_thread+0xa47/0xfb0 kernel/workqueue.c:3486
kthread+0x388/0x470 kernel/kthread.c:436
ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
</TASK>
----------------
Code disassembly (best guess):
0: 49 81 c7 70 01 00 00 add $0x170,%r15
7: 4c 8d 35 d6 00 cd 0e lea 0xecd00d6(%rip),%r14 # 0xecd00e4
e: 48 89 f8 mov %rdi,%rax
11: 48 c1 e8 03 shr $0x3,%rax
15: 80 3c 18 00 cmpb $0x0,(%rax,%rbx,1)
19: 74 05 je 0x20
1b: e8 a4 6c a8 00 call 0xa86cc4
20: 49 8b 75 18 mov 0x18(%r13),%rsi
24: 4c 89 f7 mov %r14,%rdi
27: 4c 89 fa mov %r15,%rdx
* 2a: 67 48 0f b9 3a ud1 (%edx),%rdi <-- trapping instruction
2f: 4c 89 e8 mov %r13,%rax
32: 48 c1 e8 03 shr $0x3,%rax
36: 80 3c 18 00 cmpb $0x0,(%rax,%rbx,1)
3a: 74 08 je 0x44
3c: 4c 89 ef mov %r13,%rdi
3f: e8 .byte 0xe8
* Struck through repros no longer work on HEAD.