general protection fault in l2cap_chan_connect

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 2d2791fc Linux 4.14.217
git tree: linux-4.14.y
console output: https://syzkaller.appspot.com/x/log.txt?x=10b7a7f0d00000
kernel config: https://syzkaller.appspot.com/x/.config?x=80753487c013c9c7
dashboard link: https://syzkaller.appspot.com/bug?extid=b5197488ea560887f4a6
compiler: gcc (GCC) 10.1.0-syz 20200507
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=17b571b4d00000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+b51974...@syzkaller.appspotmail.com

IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_batadv: link becomes ready
kasan: CONFIG_KASAN_INLINE enabled
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: 1 PID: 18437 Comm: syz-executor.0 Not tainted 4.14.217-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff88809c95c1c0 task.stack: ffff888087160000
RIP: 0010:__l2cap_get_chan_by_dcid net/bluetooth/l2cap_core.c:97 [inline]
RIP: 0010:l2cap_chan_connect+0x8d1/0x17f0 net/bluetooth/l2cap_core.c:7249
RSP: 0018:ffff888087167ce0 EFLAGS: 00010a03
RAX: dffffc0000000000 RBX: deacfffffffffca8 RCX: 0000000000000000
RDX: 1bd59fffffffff9b RSI: 0000000000000001 RDI: deacfffffffffcdc
RBP: ffff8880b175e6b0 R08: 0000000000000000 R09: 0000000000040628
R10: ffff88809c95ca98 R11: ffff88809c95c1c0 R12: 00000000000007ff
R13: ffff8880a01a263f R14: ffff8880958e0f80 R15: ffff8880a01a2620
FS: 00007f2077acf700(0000) GS:ffff8880ba500000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000004d0920 CR3: 0000000098f0f000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
l2cap_sock_connect+0x297/0x520 net/bluetooth/l2cap_sock.c:238
SYSC_connect net/socket.c:1655 [inline]
SyS_connect+0x1f4/0x240 net/socket.c:1636
do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
entry_SYSCALL_64_after_hwframe+0x46/0xbb
RIP: 0033:0x45e219
RSP: 002b:00007f2077acec68 EFLAGS: 00000246 ORIG_RAX: 000000000000002a
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 000000000045e219
RDX: 000000000000000e RSI: 0000000020000040 RDI: 0000000000000004
RBP: 000000000119bfc0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000119bf8c
R13: 00007ffd4cb6275f R14: 00007f2077acf9c0 R15: 000000000119bf8c
Code: 00 48 8d 9a a8 fb ff ff 48 39 d5 0f 84 e5 01 00 00 e8 94 82 ed fa 48 8d 7b 34 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <0f> b6 0c 02 48 89 fa 83 e2 07 83 c2 01 38 ca 7c 08 84 c9 0f 85
RIP: __l2cap_get_chan_by_dcid net/bluetooth/l2cap_core.c:97 [inline] RSP: ffff888087167ce0
RIP: l2cap_chan_connect+0x8d1/0x17f0 net/bluetooth/l2cap_core.c:7249 RSP: ffff888087167ce0
---[ end trace 5081dae22ae06732 ]---


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