general protection fault in __bfs

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: cbfa1702 Linux 4.14.198
git tree: linux-4.14.y
console output: https://syzkaller.appspot.com/x/log.txt?x=106a509b900000
kernel config: https://syzkaller.appspot.com/x/.config?x=3990958d85b55e59
dashboard link: https://syzkaller.appspot.com/bug?extid=801cbece6e387313f191
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+801cbe...@syzkaller.appspotmail.com

batman_adv: It is strongly recommended to keep mac addresses unique to avoid problems!
batman_adv: The newly added mac address (aa:aa:aa:aa:aa:3e) already exists on: batadv_slave_1
kasan: CONFIG_KASAN_INLINE enabled
batman_adv: It is strongly recommended to keep mac addresses unique to avoid problems!
kasan: GPF could be caused by NULL-ptr deref or user memory access
general protection fault: 0000 [#1] PREEMPT SMP KASAN
Modules linked in:
CPU: 0 PID: 6414 Comm: kworker/0:3 Not tainted 4.14.198-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: events l2cap_chan_timeout
batman_adv: The newly added mac address (aa:aa:aa:aa:aa:3e) already exists on: batadv_slave_1
task: ffff8880568ea6c0 task.stack: ffff8880568f0000
RIP: 0010:lock_accessed kernel/locking/lockdep.c:979 [inline]
RIP: 0010:__bfs.part.0+0x20e/0x470 kernel/locking/lockdep.c:1045
RSP: 0018:ffff8880568f7818 EFLAGS: 00010003
batman_adv: It is strongly recommended to keep mac addresses unique to avoid problems!
RAX: 0000000001d726dc RBX: ffffffff8a302e60 RCX: 0000000000000000
RDX: 0000000000000002 RSI: 0000000000000000 RDI: 0000000000000010
RBP: ffff8880568f78d0 R08: 0000000000000000 R09: 0000000000003940
R10: 000000000011e148 R11: 0000000000058071 R12: ffffffff814671c0
R13: 0000000000000000 R14: 0000000000000000 R15: dffffc0000000000
FS: 0000000000000000(0000) GS:ffff8880aea00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000561aa7b1b970 CR3: 000000009433a000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
__bfs kernel/locking/lockdep.c:1424 [inline]
__bfs_backwards kernel/locking/lockdep.c:1082 [inline]
find_usage_backwards kernel/locking/lockdep.c:1424 [inline]
check_usage_backwards+0x167/0x2c0 kernel/locking/lockdep.c:2713
IPv6: ADDRCONF(NETDEV_UP): batadv_slave_1: link is not ready
batman_adv: batadv0: Interface activated: batadv_slave_1
mark_lock_irq kernel/locking/lockdep.c:2804 [inline]
mark_lock+0x3c7/0x1050 kernel/locking/lockdep.c:3194
mark_irqflags kernel/locking/lockdep.c:3086 [inline]
__lock_acquire+0xcf9/0x3f20 kernel/locking/lockdep.c:3448
lock_acquire+0x170/0x3f0 kernel/locking/lockdep.c:3998
__raw_spin_lock_bh include/linux/spinlock_api_smp.h:135 [inline]
_raw_spin_lock_bh+0x2f/0x40 kernel/locking/spinlock.c:176
spin_lock_bh include/linux/spinlock.h:322 [inline]
lock_sock_nested+0x39/0x100 net/core/sock.c:2788
l2cap_sock_teardown_cb+0x7b/0x400 net/bluetooth/l2cap_sock.c:1329
l2cap_chan_del+0xa0/0x800 net/bluetooth/l2cap_core.c:596
l2cap_chan_close+0xd5/0x770 net/bluetooth/l2cap_core.c:754
l2cap_chan_timeout+0x134/0x1e0 net/bluetooth/l2cap_core.c:427
process_one_work+0x793/0x14a0 kernel/workqueue.c:2116
worker_thread+0x5cc/0xff0 kernel/workqueue.c:2250
kthread+0x30d/0x420 kernel/kthread.c:232
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404
Code: 78 01 00 00 4d 8b 36 4c 39 f3 74 78 49 8d 7e 10 4c 89 f0 4c 8b 0d d3 9a 0f 09 48 89 fa 48 2d e0 48 36 8a 48 c1 ea 03 48 c1 f8 06 <42> 80 3c 3a 00 0f 85 28 01 00 00 49 8b 4e 10 4c 8d 41 2c 4c 89
RIP: lock_accessed kernel/locking/lockdep.c:979 [inline] RSP: ffff8880568f7818
RIP: __bfs.part.0+0x20e/0x470 kernel/locking/lockdep.c:1045 RSP: ffff8880568f7818
---[ end trace fec8668f0207bde0 ]---


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[syzbot]

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