Re: [syzbot] [bluetooth?] KASAN: slab-use-after-free Read in hci_send_acl

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
WARNING in l2cap_chan_del

------------[ cut here ]------------
WARNING: CPU: 0 PID: 780 at kernel/workqueue.c:1725 __queue_work+0xb52/0x1060 kernel/workqueue.c:1724
Modules linked in:
CPU: 0 PID: 780 Comm: kworker/0:2 Not tainted 6.5.0-rc6-next-20230818-syzkaller-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023
Workqueue: events l2cap_chan_timeout
RIP: 0010:__queue_work+0xb52/0x1060 kernel/workqueue.c:1724
Code: 03 38 d0 7c 09 84 d2 74 05 e8 ea 54 87 00 8b 5b 2c 31 ff 83 e3 20 89 de e8 5b cf 31 00 85 db 0f 85 7f 01 00 00 e8 de d3 31 00 <0f> 0b e9 ca fa ff ff e8 d2 d3 31 00 0f 0b e9 76 fa ff ff e8 c6 d3
RSP: 0018:ffffc900046d7ac8 EFLAGS: 00010093
RAX: 0000000000000000 RBX: ffff888013650000 RCX: 0000000000000000
RDX: ffff88801d4d1dc0 RSI: ffffffff8155ff92 RDI: ffff888013650008
RBP: 0000000000000000 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000200000 R11: 0000000000000000 R12: ffff88806a634270
R13: ffffffff81dd2d93 R14: ffff88806a6342b8 R15: ffffffff81dd2d93
FS:  0000000000000000(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f98dec6b6c0 CR3: 000000000c976000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 __queue_delayed_work+0x1bf/0x260 kernel/workqueue.c:1950
 queue_delayed_work_on+0x106/0x130 kernel/workqueue.c:1986
 queue_delayed_work include/linux/workqueue.h:569 [inline]
 hci_conn_drop include/net/bluetooth/hci_core.h:1549 [inline]
 hci_conn_drop include/net/bluetooth/hci_core.h:1519 [inline]
 l2cap_chan_del+0x389/0x9b0 net/bluetooth/l2cap_core.c:659
 l2cap_chan_close+0xff/0xa20 net/bluetooth/l2cap_core.c:842
 l2cap_chan_timeout+0x17d/0x2f0 net/bluetooth/l2cap_core.c:452
 process_one_work+0x887/0x15d0 kernel/workqueue.c:2630
 process_scheduled_works kernel/workqueue.c:2703 [inline]
 worker_thread+0x8bb/0x1290 kernel/workqueue.c:2784
 kthread+0x33a/0x430 kernel/kthread.c:388
 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:304
 </TASK>


Tested on:

commit:         7271b2a5 Add linux-next specific files for 20230818
git tree:       https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git
console output: https://syzkaller.appspot.com/x/log.txt?x=1333e4dfa80000
kernel config:  https://syzkaller.appspot.com/x/.config?x=1936af09cdef7dd6
dashboard link: https://syzkaller.appspot.com/bug?extid=a0c80b06ae2cb8895bc4
compiler:       gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
patch:          https://syzkaller.appspot.com/x/patch.diff?x=1361735ba80000