linux-kernel - [syzbot] [bluetooth?] WARNING in l2cap_send_disconn

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Message-ID: <687f34f7.a70a0220.21b99c.0008.GAE@google.com>
Date: Mon, 21 Jul 2025 23:51:35 -0700
From: syzbot <syzbot+e487b7a18d6f21a9811c@...kaller.appspotmail.com>
To: johan.hedberg@...il.com, linux-bluetooth@...r.kernel.org, 
	linux-kernel@...r.kernel.org, luiz.dentz@...il.com, marcel@...tmann.org, 
	syzkaller-bugs@...glegroups.com
Subject: [syzbot] [bluetooth?] WARNING in l2cap_send_disconn_req (2)

Hello,

syzbot found the following issue on:

HEAD commit:    6832a9317eee Merge tag 'net-6.16-rc7' of git://git.kernel...
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=127117d4580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=8bff2df4655c5f44
dashboard link: https://syzkaller.appspot.com/bug?extid=e487b7a18d6f21a9811c
compiler:       Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/818bd549a31a/disk-6832a931.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/f971d7bc88e2/vmlinux-6832a931.xz
kernel image: https://storage.googleapis.com/syzbot-assets/f637a5f4829c/bzImage-6832a931.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+e487b7a18d6f21a9811c@...kaller.appspotmail.com

------------[ cut here ]------------
workqueue: cannot queue hci_tx_work on wq hci2
WARNING: CPU: 0 PID: 981 at kernel/workqueue.c:2258 __queue_work+0xd62/0xfe0 kernel/workqueue.c:2256
Modules linked in:
CPU: 0 UID: 0 PID: 981 Comm: kworker/0:3 Not tainted 6.16.0-rc6-syzkaller-00121-g6832a9317eee #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Workqueue: events l2cap_chan_timeout
RIP: 0010:__queue_work+0xd62/0xfe0 kernel/workqueue.c:2256
Code: 42 80 3c 20 00 74 08 4c 89 ef e8 a9 2d 95 00 49 8b 75 00 49 81 c7 78 01 00 00 48 c7 c7 00 e9 89 8b 4c 89 fa e8 5f 34 f9 ff 90 <0f> 0b 90 90 e9 f1 f4 ff ff e8 c0 46 35 00 90 0f 0b 90 e9 dd fc ff
RSP: 0018:ffffc90003a4f728 EFLAGS: 00010046
RAX: 2e4141edcce3d000 RBX: 0000000000000020 RCX: ffff8880256a8000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000002
RBP: 1ffff11028876538 R08: ffff8880b8624293 R09: 1ffff110170c4852
R10: dffffc0000000000 R11: ffffed10170c4853 R12: dffffc0000000000
R13: ffff88806c564b68 R14: ffff88801a494008 R15: ffff8881443b2978
FS:  0000000000000000(0000) GS:ffff888125c59000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c25779d CR3: 000000003202e000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 queue_work_on+0x181/0x270 kernel/workqueue.c:2392
 l2cap_send_disconn_req+0x255/0x3c0 net/bluetooth/l2cap_core.c:1495
 l2cap_chan_close+0x3ad/0x980 net/bluetooth/l2cap_core.c:823
 l2cap_chan_timeout+0x158/0x390 net/bluetooth/l2cap_core.c:431
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0xade/0x17b0 kernel/workqueue.c:3321
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3402
 kthread+0x711/0x8a0 kernel/kthread.c:464
 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>


---
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