syzbot

IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_bridge: link becomes ready
IPv6: ADDRCONF(NETDEV_UP): veth0: link is not ready
IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready
l2tp_core: tunl 4: sockfd_lookup(fd=5) returned -9
kasan: CONFIG_KASAN_INLINE enabled
kasan: GPF could be caused by NULL-ptr deref or user memory accessgeneral protection fault: 0000 [#1] PREEMPT SMP KASAN
Dumping ftrace buffer:
   (ftrace buffer empty)
Modules linked in:
CPU: 0 PID: 4460 Comm: syz-executor0 Not tainted 4.4.151-ge917467 #84
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8801c9f71800 task.stack: ffff8801c9f90000
RIP: 0010:[<ffffffff835adfb3>]  [<ffffffff835adfb3>] __read_once_size include/linux/compiler.h:218 [inline]
RIP: 0010:[<ffffffff835adfb3>]  [<ffffffff835adfb3>] sk_dst_get include/net/sock.h:1740 [inline]
RIP: 0010:[<ffffffff835adfb3>]  [<ffffffff835adfb3>] pppol2tp_connect+0x873/0x1910 net/l2tp/l2tp_ppp.c:762
RSP: 0018:ffff8801c9f97bc8  EFLAGS: 00010202
RAX: dffffc0000000000 RBX: ffff8800b7bdee80 RCX: 1ffffffff0942ce0
RDX: 000000000000003b RSI: ffffffff835adf9b RDI: 00000000000001d8
RBP: ffff8801c9f97d78 R08: ffff8801c9f72128 R09: 0000000000000000
R10: 0000000000000001 R11: ffff8801c9f71800 R12: ffff8801da2f5900
R13: ffff8800b7bdeeb0 R14: 0000000000000000 R15: ffff8801d658aa00
FS:  00007f40bc392700(0000) GS:ffff8801db200000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020000180 CR3: 00000001da122000 CR4: 00000000001606f0
Stack:
 ffffffff835adf3b 0000000200000005 ffff8801c9f97cd0 ffff880100000000
 ffff8800b7bdf250 ffff8800b7bdee92 1ffff100393f2f82 ffff8801da2f5a98
 ffff8801d658ab80 0000000041b58ab3 ffffffff8424e778 ffffffff835ad740
Call Trace:
 [<ffffffff82f27758>] SYSC_connect+0x1b8/0x300 net/socket.c:1558
 [<ffffffff82f2a094>] SyS_connect+0x24/0x30 net/socket.c:1539
 [<ffffffff838cc125>] entry_SYSCALL_64_fastpath+0x22/0x9e
Code: fd 80 3d e0 75 45 01 00 0f 84 44 09 00 00 e8 65 66 da fd 49 8d be d8 01 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 60 0d 00 00 4d 8b be d8 01 00 00 e8 57 c5 cc 
RIP  [<ffffffff835adfb3>] __read_once_size include/linux/compiler.h:218 [inline]
RIP  [<ffffffff835adfb3>] sk_dst_get include/net/sock.h:1740 [inline]
RIP  [<ffffffff835adfb3>] pppol2tp_connect+0x873/0x1910 net/l2tp/l2tp_ppp.c:762
 RSP <ffff8801c9f97bc8>
---[ end trace 774a0a230f675e3b ]---