BUG: corrupted list in hci_chan_del

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 7f2c5eb4 Linux 4.14.191
git tree: linux-4.14.y
console output: https://syzkaller.appspot.com/x/log.txt?x=14dfc632900000
kernel config: https://syzkaller.appspot.com/x/.config?x=881f1aee9620bf9f
dashboard link: https://syzkaller.appspot.com/bug?extid=00e5b4564afe21c075b5
compiler: gcc (GCC) 10.1.0-syz 20200507

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

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+00e5b4...@syzkaller.appspotmail.com

list_del corruption. prev->next should be ffff88808538dcc0, but was (null)
------------[ cut here ]------------
kernel BUG at lib/list_debug.c:51!
invalid opcode: 0000 [#1] PREEMPT SMP KASAN
Modules linked in:
CPU: 0 PID: 10159 Comm: syz-executor.1 Not tainted 4.14.191-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff888082c1a580 task.stack: ffff88805a0f8000
RIP: 0010:__list_del_entry_valid.cold+0xf/0x55 lib/list_debug.c:51
RSP: 0018:ffff88805a0ff840 EFLAGS: 00010282
RAX: 0000000000000054 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff86ac0dc0 RDI: ffffed100b41fefe
RBP: ffff88808538dcc0 R08: 0000000000000054 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffff88808ecfaf00
R13: ffffffff8750f4e0 R14: 0000000000000067 R15: ffffffff85b74830
FS: 00007fd366e50700(0000) GS:ffff8880aea00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fa323149590 CR3: 0000000007c6a000 CR4: 00000000001406f0
DR0: 0000000020000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600
Call Trace:
__list_del_entry include/linux/list.h:117 [inline]
list_del_rcu include/linux/rculist.h:130 [inline]
hci_chan_del+0x3f/0x180 net/bluetooth/hci_conn.c:1552
l2cap_conn_del+0x417/0x670 net/bluetooth/l2cap_core.c:1736
l2cap_disconn_cfm net/bluetooth/l2cap_core.c:7435 [inline]
l2cap_disconn_cfm+0x6b/0x80 net/bluetooth/l2cap_core.c:7428
hci_disconn_cfm include/net/bluetooth/hci_core.h:1226 [inline]
hci_conn_hash_flush+0x114/0x220 net/bluetooth/hci_conn.c:1376
hci_dev_do_close+0x542/0xc50 net/bluetooth/hci_core.c:1620
hci_unregister_dev+0x170/0x7a0 net/bluetooth/hci_core.c:3191
vhci_release+0x70/0xe0 drivers/bluetooth/hci_vhci.c:354
__fput+0x25f/0x7a0 fs/file_table.c:210
task_work_run+0x11f/0x190 kernel/task_work.c:113
exit_task_work include/linux/task_work.h:22 [inline]
do_exit+0xa08/0x27f0 kernel/exit.c:865
do_group_exit+0x100/0x2e0 kernel/exit.c:962
get_signal+0x38d/0x1ca0 kernel/signal.c:2423
do_signal+0x7c/0x1550 arch/x86/kernel/signal.c:814
exit_to_usermode_loop+0x160/0x200 arch/x86/entry/common.c:160
prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline]
syscall_return_slowpath arch/x86/entry/common.c:270 [inline]
do_syscall_64+0x4a3/0x640 arch/x86/entry/common.c:297
entry_SYSCALL_64_after_hwframe+0x46/0xbb
RIP: 0033:0x45cce9
RSP: 002b:00007fd366e4fcf8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 000000000078bf08 RCX: 000000000045cce9
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 000000000078bf08
RBP: 000000000078bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000078bf0c
R13: 00007ffd2094edcf R14: 00007fd366e509c0 R15: 000000000078bf0c
Code: 86 e8 1c b4 44 fe 0f 0b 48 89 f1 48 c7 c7 00 5c e4 86 4c 89 e6 e8 08 b4 44 fe 0f 0b 48 89 ee 48 c7 c7 a0 5d e4 86 e8 f7 b3 44 fe <0f> 0b 4c 89 ea 48 89 ee 48 c7 c7 e0 5c e4 86 e8 e3 b3 44 fe 0f
RIP: __list_del_entry_valid.cold+0xf/0x55 lib/list_debug.c:51 RSP: ffff88805a0ff840
---[ end trace 979a0fdc132e834d ]---


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[syzbot]

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