[v6.6] BUG: corrupted list in hci_cmd_sync_dequeue_once

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: c2603c511feb Linux 6.6.93
git tree: linux-6.6.y
console output: https://syzkaller.appspot.com/x/log.txt?x=136a190c580000
kernel config: https://syzkaller.appspot.com/x/.config?x=486bade17c8c30b9
dashboard link: https://syzkaller.appspot.com/bug?extid=d048b8cbd69df42fa6e4
compiler: Debian clang version 20.1.6 (++20250514063057+1e4d39e07757-1~exp1~20250514183223.118), Debian LLD 20.1.6

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/8754f950a6e7/disk-c2603c51.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/3b19332dbf63/vmlinux-c2603c51.xz
kernel image: https://storage.googleapis.com/syzbot-assets/cb245e836038/bzImage-c2603c51.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+d048b8...@syzkaller.appspotmail.com

list_del corruption, ffff88805f901a00->next is LIST_POISON1 (dead000000000100)
------------[ cut here ]------------
kernel BUG at lib/list_debug.c:58!
invalid opcode: 0000 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 5774 Comm: kworker/u5:2 Not tainted 6.6.93-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Workqueue: hci3 hci_conn_timeout
RIP: 0010:__list_del_entry_valid_or_report+0xe9/0x130 lib/list_debug.c:56
Code: 48 89 de e8 29 7e 34 06 0f 0b 48 c7 c7 00 6b fc 8a 48 89 de e8 18 7e 34 06 0f 0b 48 c7 c7 60 6b fc 8a 48 89 de e8 07 7e 34 06 <0f> 0b 48 c7 c7 c0 6b fc 8a 48 89 de e8 f6 7d 34 06 0f 0b 48 c7 c7
RSP: 0018:ffffc900045cfac8 EFLAGS: 00010246
RAX: 000000000000004e RBX: ffff88805f901a00 RCX: 3b5c73d431bd4800
RDX: 0000000000000000 RSI: 0000000080000000 RDI: 0000000000000000
RBP: ffffffff89790a30 R08: ffffc900045cf7c7 R09: 1ffff920008b9ef8
R10: dffffc0000000000 R11: fffff520008b9ef9 R12: dffffc0000000000
R13: 1ffff1100bf20340 R14: dead000000000100 R15: dead000000000122
FS: 0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f395b2a4f22 CR3: 000000002c55a000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
__list_del_entry_valid include/linux/list.h:124 [inline]
__list_del_entry include/linux/list.h:215 [inline]
list_del include/linux/list.h:229 [inline]
_hci_cmd_sync_cancel_entry net/bluetooth/hci_sync.c:665 [inline]
hci_cmd_sync_cancel_entry net/bluetooth/hci_sync.c:869 [inline]
hci_cmd_sync_dequeue_once+0x244/0x370 net/bluetooth/hci_sync.c:888
hci_cancel_connect_sync+0xc8/0x120 net/bluetooth/hci_sync.c:-1
hci_abort_conn+0x18c/0x330 net/bluetooth/hci_conn.c:2898
process_one_work kernel/workqueue.c:2634 [inline]
process_scheduled_works+0xa45/0x15b0 kernel/workqueue.c:2711
worker_thread+0xa55/0xfc0 kernel/workqueue.c:2792
kthread+0x2fa/0x390 kernel/kthread.c:388
ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:__list_del_entry_valid_or_report+0xe9/0x130 lib/list_debug.c:56
Code: 48 89 de e8 29 7e 34 06 0f 0b 48 c7 c7 00 6b fc 8a 48 89 de e8 18 7e 34 06 0f 0b 48 c7 c7 60 6b fc 8a 48 89 de e8 07 7e 34 06 <0f> 0b 48 c7 c7 c0 6b fc 8a 48 89 de e8 f6 7d 34 06 0f 0b 48 c7 c7
RSP: 0018:ffffc900045cfac8 EFLAGS: 00010246
RAX: 000000000000004e RBX: ffff88805f901a00 RCX: 3b5c73d431bd4800
RDX: 0000000000000000 RSI: 0000000080000000 RDI: 0000000000000000
RBP: ffffffff89790a30 R08: ffffc900045cf7c7 R09: 1ffff920008b9ef8
R10: dffffc0000000000 R11: fffff520008b9ef9 R12: dffffc0000000000
R13: 1ffff1100bf20340 R14: dead000000000100 R15: dead000000000122
FS: 0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c300462 CR3: 000000002c55a000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400


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[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.