BUG: unable to handle kernel NULL pointer dereference at           (null)
IP:           (null)
PGD 1fcb49067 P4D 1fcb49067 PUD 1fd585067 PMD 0 
Oops: 0010 [#1] SMP
Dumping ftrace buffer:
   (ftrace buffer empty)
Modules linked in:
CPU: 1 PID: 23193 Comm: syz-executor7 Not tainted 4.15.0-rc3-next-20171214+ #67
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:          (null)
RSP: 0018:ffffc90001417998 EFLAGS: 00010216
RAX: 0000000000010000 RBX: ffff8801f8066200 RCX: ffffffff8167e521
RDX: 0000000000000002 RSI: ffff880211d5c448 RDI: ffff8801f8066200
RBP: ffffc900014179d8 R08: 000000000002bcf8 R09: ffff8801faec7200
R10: 0000000000000000 R11: 0000000000000000 R12: ffff880211d5c448
R13: 0000000000000002 R14: 0000000000000198 R15: ffff8801fae16850
FS:  00007f21194af700(0000) GS:ffff88021fd00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 00000001fc7d0006 CR4: 00000000001606e0
Call Trace:
 shash_async_setkey+0x29/0x30 crypto/shash.c:208
 crypto_ahash_setkey+0x40/0xc0 crypto/ahash.c:200
 ah6_init_state+0xaa/0x1d0 net/ipv6/ah6.c:704
 __xfrm_init_state+0x25d/0x660 net/xfrm/xfrm_state.c:2259
 xfrm_init_state+0x1c/0x20 net/xfrm/xfrm_state.c:2285
 pfkey_msg2xfrm_state net/key/af_key.c:1274 [inline]
 pfkey_add+0x6ed/0xbf0 net/key/af_key.c:1491
 pfkey_process+0x255/0x290 net/key/af_key.c:2809
 pfkey_sendmsg+0x193/0x310 net/key/af_key.c:3648
 sock_sendmsg_nosec net/socket.c:636 [inline]
 sock_sendmsg+0x51/0x70 net/socket.c:646
 ___sys_sendmsg+0x35e/0x3b0 net/socket.c:2026
 __sys_sendmsg+0x50/0x90 net/socket.c:2060
 SYSC_sendmsg net/socket.c:2071 [inline]
 SyS_sendmsg+0x2d/0x50 net/socket.c:2067
 entry_SYSCALL_64_fastpath+0x1f/0x96
RIP: 0033:0x452a09
RSP: 002b:00007f21194aec58 EFLAGS: 00000212 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 000000000071bea0 RCX: 0000000000452a09
RDX: 0000000000000000 RSI: 00000000205f5000 RDI: 0000000000000013
RBP: 0000000000000393 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000212 R12: 00000000006f2668
R13: 00000000ffffffff R14: 00007f21194af6d4 R15: 0000000000000000
Code:  Bad RIP value.
RIP:           (null) RSP: ffffc90001417998
CR2: 0000000000000000
---[ end trace 471743122416af23 ]---