------------[ cut here ]------------
WARNING: CPU: 0 PID: 30399 at net/xfrm/xfrm_policy.c:764 xfrm_policy_insert+0x38b/0x3e0 net/xfrm/xfrm_policy.c:764()
Kernel panic - not syncing: panic_on_warn set ...

CPU: 0 PID: 30399 Comm: syz-executor Not tainted 4.1.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 ffffffff824dda50 ffff880215aff928 ffffffff81fb9ae4 0000000000000032
 ffffffff824200ae ffff880215aff9a8 ffffffff81fb7a81 ffff880215aff948
 ffffffff00000008 ffff880215aff9b8 ffff880215aff958 0000000000000000
Call Trace:
 [<ffffffff81fb9ae4>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81fb9ae4>] dump_stack+0x4c/0x65 lib/dump_stack.c:50
 [<ffffffff81fb7a81>] panic+0xcd/0x211 kernel/panic.c:111
 [<ffffffff8116b87b>] warn_slowpath_common+0xbb/0xc0 kernel/panic.c:442
 [<ffffffff8116b925>] warn_slowpath_null+0x15/0x20 kernel/panic.c:479
 [<ffffffff81cc835b>] xfrm_policy_insert+0x38b/0x3e0 net/xfrm/xfrm_policy.c:764
 [<ffffffff81cd7e28>] xfrm_add_policy+0xa8/0x140 net/xfrm/xfrm_user.c:1504
 [<ffffffff81cd6e29>] xfrm_user_rcv_msg+0x109/0x1d0 net/xfrm/xfrm_user.c:2466
 [<ffffffff81b83659>] netlink_rcv_skb+0xa9/0xd0 net/netlink/af_netlink.c:2843
 [<ffffffff81cd6052>] xfrm_netlink_rcv+0x32/0x40 net/xfrm/xfrm_user.c:2474
 [<ffffffff81b82f9e>] netlink_unicast_kernel net/netlink/af_netlink.c:1763 [inline]
 [<ffffffff81b82f9e>] netlink_unicast+0x1ce/0x2f0 net/netlink/af_netlink.c:1789
 [<ffffffff81b833d0>] netlink_sendmsg+0x310/0x3d0 net/netlink/af_netlink.c:2353
 [<ffffffff81af90d5>] sock_sendmsg_nosec net/socket.c:613 [inline]
 [<ffffffff81af90d5>] sock_sendmsg+0x35/0x40 net/socket.c:623
 [<ffffffff81af9b03>] ___sys_sendmsg+0x2d3/0x2e0 net/socket.c:1955
 [<ffffffff81afab9d>] __sys_sendmsg+0x3d/0x80 net/socket.c:1989
 [<ffffffff81afabed>] SYSC_sendmsg net/socket.c:2000 [inline]
 [<ffffffff81afabed>] SyS_sendmsg+0xd/0x20 net/socket.c:1996
 [<ffffffff81fc9e32>] system_call_fastpath+0x16/0x7a
Kernel Offset: disabled