ip (3967) used greatest stack depth: 23976 bytes left
IPv6: ADDRCONF(NETDEV_UP): veth0: link is not ready
IPv6: ADDRCONF(NETDEV_UP): veth1: link is not ready
IPv6: ADDRCONF(NETDEV_CHANGE): veth1: link becomes ready
IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready
BUG: unable to handle kernel NULL pointer dereference at 0000000000000080
IP: [<ffffffff836c8e30>] sock_hold include/net/sock.h:584 [inline]
IP: [<ffffffff836c8e30>] l2tp_session_create+0xc60/0x16f0 net/l2tp/l2tp_core.c:1911
PGD 1d713f067 [   38.429519] PUD 1d98ab067 
Oops: 0002 [#1] PREEMPT SMP KASAN
Dumping ftrace buffer:
   (ftrace buffer empty)
Modules linked in:
CPU: 1 PID: 4207 Comm: syz-executor0 Not tainted 4.9.123-g8dd3fc2 #31
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8801d5ee3000 task.stack: ffff8801d69b0000
RIP: 0010:[<ffffffff836c8e30>]  [<ffffffff836c8e30>] sock_hold include/net/sock.h:584 [inline]
RIP: 0010:[<ffffffff836c8e30>]  [<ffffffff836c8e30>] l2tp_session_create+0xc60/0x16f0 net/l2tp/l2tp_core.c:1911
RSP: 0018:ffff8801d69b7ab0  EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffff8801da266000 RCX: 1ffff1003abdc71d
RDX: 1ffff1003adc4b50 RSI: ffff8801d5ee38c8 RDI: ffff8801d6e25a80
RBP: ffff8801d69b7b50 R08: ffff8801d5ee38e8 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffff8801d6e25958
R13: 0000000000000000 R14: ffff8801d6e25900 R15: ffff8801d69b7c68
FS:  0000000000000000(0000) GS:ffff8801db300000(0063) knlGS:00000000f7776b40
CS:  0010 DS: 002b ES: 002b CR0: 0000000080050033
CR2: 0000000000000080 CR3: 00000001da2bd000 CR4: 00000000001606f0
Stack:
 0000000000000201 ffffffff836ca141 ffff8801d69b7ad0 ffffffff81237f0d
 ffff8801d6e25900 ffff8801da266158 ffff8801d6e25958 ffff8801da266150
 ffff8801da2660b0 ffff8801d6e25920 0000000000000000 0000000000000000
Call Trace:
 [<ffffffff836cdfe7>] pppol2tp_connect+0x10d7/0x18f0 net/l2tp/l2tp_ppp.c:718
 [<ffffffff8301e958>] SYSC_connect+0x1b8/0x300 net/socket.c:1563
 [<ffffffff83021224>] SyS_connect+0x24/0x30 net/socket.c:1544
 [<ffffffff81006da7>] do_syscall_32_irqs_on arch/x86/entry/common.c:325 [inline]
 [<ffffffff81006da7>] do_fast_syscall_32+0x2f7/0x870 arch/x86/entry/common.c:387
 [<ffffffff83a03390>] entry_SYSENTER_compat+0x90/0xa2 arch/x86/entry/entry_64_compat.S:137
Code: 00 00 49 8d be 80 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 7b 09 00 00 49 8b 86 80 01 00 00 <f0> ff 80 80 00 00 00 48 b8 00 00 00 00 00 fc ff df 48 8b 55 d0 
RIP  [<ffffffff836c8e30>] sock_hold include/net/sock.h:584 [inline]
RIP  [<ffffffff836c8e30>] l2tp_session_create+0xc60/0x16f0 net/l2tp/l2tp_core.c:1911
 RSP <ffff8801d69b7ab0>
CR2: 0000000000000080
---[ end trace 8fa50bc58ba96876 ]---