IPv6: NLM_F_REPLACE set, but no existing node found!
kasan: CONFIG_KASAN_INLINE enabled
kasan: GPF could be caused by NULL-ptr deref or user memory access
general protection fault: 0000 [#1] SMP KASAN
Dumping ftrace buffer:
   (ftrace buffer empty)
Modules linked in:
CPU: 1 PID: 5136 Comm: syz-executor3 Not tainted 4.13.0-rc4+ #4
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8801c7e6c1c0 task.stack: ffff8801c7110000
RIP: 0010:__ipv6_prefix_equal64_half include/net/ipv6.h:486 [inline]
RIP: 0010:ipv6_prefix_equal include/net/ipv6.h:503 [inline]
RIP: 0010:fib6_add_1 net/ipv6/ip6_fib.c:590 [inline]
RIP: 0010:fib6_add+0x6f8/0x33e0 net/ipv6/ip6_fib.c:1086
RSP: 0018:ffff8801c7117140 EFLAGS: 00010202
RAX: 0000000000000020 RBX: 0000000000000001 RCX: ffffc90003cde000
RDX: 00000000000004e0 RSI: ffffffff842f28da RDI: 0000000000000100
RBP: ffff8801c7117360 R08: ffff8801c7117958 R09: 0000000000000004
R10: ffff8801c7117228 R11: ffffffff842cf2a6 R12: dffffc0000000000
R13: 0000000000000000 R14: ffff8801d66f1500 R15: 0000000000000000
FS:  00007ff1b5e1c700(0000) GS:ffff8801db300000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020000000 CR3: 00000001cbdf5000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 __ip6_ins_rt+0x6c/0x90 net/ipv6/route.c:948
 ip6_route_add+0x148/0x1a0 net/ipv6/route.c:2119
 inet6_rtm_newroute+0x139/0x150 net/ipv6/route.c:3291
 rtnetlink_rcv_msg+0x733/0x1090 net/core/rtnetlink.c:4246
 netlink_rcv_skb+0x216/0x440 net/netlink/af_netlink.c:2397
 rtnetlink_rcv+0x1c/0x20 net/core/rtnetlink.c:4258
 netlink_unicast_kernel net/netlink/af_netlink.c:1265 [inline]
 netlink_unicast+0x4e8/0x6f0 net/netlink/af_netlink.c:1291
 netlink_sendmsg+0xa4a/0xe60 net/netlink/af_netlink.c:1854
 sock_sendmsg_nosec net/socket.c:633 [inline]
 sock_sendmsg+0xca/0x110 net/socket.c:643
 sock_write_iter+0x31a/0x5d0 net/socket.c:912
 call_write_iter include/linux/fs.h:1743 [inline]
 new_sync_write fs/read_write.c:457 [inline]
 __vfs_write+0x684/0x970 fs/read_write.c:470
 vfs_write+0x189/0x510 fs/read_write.c:518
 SYSC_write fs/read_write.c:565 [inline]
 SyS_write+0xef/0x220 fs/read_write.c:557
 entry_SYSCALL_64_fastpath+0x1f/0xbe
RIP: 0033:0x4512e9
RSP: 002b:00007ff1b5e1bc08 EFLAGS: 00000216 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00000000007180a8 RCX: 00000000004512e9
RDX: 0000000000000022 RSI: 0000000020b95fde RDI: 0000000000000022
RBP: 0000000000000086 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000216 R12: 00000000004b69bf
R13: 00000000ffffffff R14: 0000000000000000 R15: 0000000000000000
Code: c8 24 00 00 49 89 1e 49 89 de e9 f0 02 00 00 e8 cf ce 3e fd 85 db 74 66 e8 c6 ce 3e fd 49 8d bd 00 01 00 00 48 89 f8 48 c1 e8 03 <42> 80 3c 20 00 0f 85 0d 2b 00 00 48 8b 85 60 fe ff ff 49 8b 95 
RIP: __ipv6_prefix_equal64_half include/net/ipv6.h:486 [inline] RSP: ffff8801c7117140
RIP: ipv6_prefix_equal include/net/ipv6.h:503 [inline] RSP: ffff8801c7117140
RIP: fib6_add_1 net/ipv6/ip6_fib.c:590 [inline] RSP: ffff8801c7117140
RIP: fib6_add+0x6f8/0x33e0 net/ipv6/ip6_fib.c:1086 RSP: ffff8801c7117140
---[ end trace 1d2df3c593c500a7 ]---