syzbot

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: 3006 Comm: syzkaller479706 Not tainted 4.13.0-rc5+ #42
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8801d19e23c0 task.stack: ffff8801d00b8000
RIP: 0010:fib_dump_info+0x3aa/0x13b0 net/ipv4/fib_semantics.c:1316
RSP: 0018:ffff8801d00beeb0 EFLAGS: 00010206
RAX: dffffc0000000000 RBX: 00000000000000fe RCX: 0000000000000000
RDX: 0000000000000006 RSI: 0000000000000002 RDI: 0000000000000030
RBP: ffff8801d00bf108 R08: ffffed003a040149 R09: ffffed003a040149
R10: 0000000000000001 R11: ffffed003a040148 R12: ffff8801d0200a35
R13: 0000000000000099 R14: ffff8801d0200a24 R15: ffff8801d12aadc0
FS:  0000000000717880(0000) GS:ffff8801db300000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020b9b000 CR3: 00000001cf6fb000 CR4: 00000000001406e0
Call Trace:
 inet_rtm_getroute+0xf9c/0x2d60 net/ipv4/route.c:2767
 rtnetlink_rcv_msg+0x5ea/0x840 net/core/rtnetlink.c:4217
 netlink_rcv_skb+0x216/0x440 net/netlink/af_netlink.c:2397
 rtnetlink_rcv+0x2a/0x40 net/core/rtnetlink.c:4223
 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:898
 call_write_iter include/linux/fs.h:1743 [inline]
 do_iter_readv_writev+0x525/0x7f0 fs/read_write.c:650
 do_iter_write+0x154/0x540 fs/read_write.c:929
 vfs_writev+0x18a/0x340 fs/read_write.c:975
 do_writev+0xfc/0x2a0 fs/read_write.c:1011
 SYSC_writev fs/read_write.c:1084 [inline]
 SyS_writev+0x27/0x30 fs/read_write.c:1081
 entry_SYSCALL_64_fastpath+0x1f/0xbe
RIP: 0033:0x43fd09
RSP: 002b:00007ffd5593e4f8 EFLAGS: 00000203 ORIG_RAX: 0000000000000014
RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 000000000043fd09
RDX: 0000000000000001 RSI: 0000000020b93000 RDI: 0000000000000003
RBP: 0000000000000086 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000203 R12: 0000000000401670
R13: 0000000000401700 R14: 0000000000000000 R15: 0000000000000000
Code: 0f b6 b5 e4 fd ff ff 48 8b 85 f0 fd ff ff 40 88 70 17 48 8b 45 28 48 8d 78 30 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <0f> b6 04 02 84 c0 74 08 3c 03 0f 8e ba 0f 00 00 48 8b 45 28 44 
RIP: fib_dump_info+0x3aa/0x13b0 net/ipv4/fib_semantics.c:1316 RSP: ffff8801d00beeb0
---[ end trace a8418f8a7cf5c5b9 ]---