BUG: KASAN: stack-out-of-bounds in xfrm_state_find+0x305b/0x3190 net/xfrm/xfrm_state.c:1051
Read of size 4 at addr ffff8801d0377af8 by task syzkaller124001/2982

CPU: 1 PID: 2982 Comm: syzkaller124001 Not tainted 4.14.0-rc2-next-20170928+ #31
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:16 [inline]
 dump_stack+0x194/0x257 lib/dump_stack.c:52
 print_address_description+0x73/0x250 mm/kasan/report.c:252
 kasan_report_error mm/kasan/report.c:351 [inline]
 kasan_report+0x25b/0x340 mm/kasan/report.c:409
 __asan_report_load4_noabort+0x14/0x20 mm/kasan/report.c:429
 xfrm_state_find+0x305b/0x3190 net/xfrm/xfrm_state.c:1051
 xfrm_tmpl_resolve_one net/xfrm/xfrm_policy.c:1388 [inline]
 xfrm_tmpl_resolve+0x309/0xc00 net/xfrm/xfrm_policy.c:1432
 xfrm_resolve_and_create_bundle+0x186/0x24b0 net/xfrm/xfrm_policy.c:1830
 xfrm_lookup+0xf0a/0x2540 net/xfrm/xfrm_policy.c:2141
 xfrm_lookup_route+0x39/0x1a0 net/xfrm/xfrm_policy.c:2259
 ip_route_output_flow+0x7c/0xa0 net/ipv4/route.c:2549
 udp_sendmsg+0x19b8/0x2cd0 net/ipv4/udp.c:1022
 inet_sendmsg+0x11f/0x5e0 net/ipv4/af_inet.c:762
 sock_sendmsg_nosec net/socket.c:633 [inline]
 sock_sendmsg+0xca/0x110 net/socket.c:643
 SYSC_sendto+0x358/0x5a0 net/socket.c:1750
 SyS_sendto+0x40/0x50 net/socket.c:1718
 entry_SYSCALL_64_fastpath+0x1f/0xbe
RIP: 0033:0x43fee9
RSP: 002b:00007ffca1bb87d8 EFLAGS: 00000217 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 000000000043fee9
RDX: 0000000000000000 RSI: 000000002010affe RDI: 0000000000000003
RBP: 0000000000000086 R08: 00000000202f9000 R09: 0000000000000010
R10: 000000002004487c R11: 0000000000000217 R12: 0000000000401850
R13: 00000000004018e0 R14: 0000000000000000 R15: 0000000000000000

The buggy address belongs to the page:
page:ffffea000740ddc0 count:0 mapcount:0 mapping:          (null) index:0x0
flags: 0x200000000000000()
raw: 0200000000000000 0000000000000000 0000000000000000 00000000ffffffff
raw: 0000000000000000 0000000100000001 0000000000000000 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801d0377980: 00 00 00 00 f1 f1 f1 f1 04 f2 f2 f2 f2 f2 f2 f2
 ffff8801d0377a00: 00 f2 f2 f2 f2 f2 f2 f2 f8 f2 f2 f2 f2 f2 f2 f2
>ffff8801d0377a80: 00 00 00 00 f2 f2 f2 f2 00 00 00 00 00 00 00 f2
                                                                ^
 ffff8801d0377b00: f2 f2 f2 f2 00 00 00 00 00 00 00 00 00 f2 f2 f2
 ffff8801d0377b80: f3 f3 f3 f3 00 00 00 00 00 00 00 00 00 00 f1 f1
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