BUG: KASAN: stack-out-of-bounds in xfrm_state_find+0x305b/0x3190 net/xfrm/xfrm_state.c:1051
Read of size 4 at addr ffff88006c50f4e0 by task syzkaller804668/3002

CPU: 1 PID: 3002 Comm: syzkaller804668 Not tainted 4.13.0-next-20170905+ #15
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 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+0x24e/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+0x2fb/0xbd0 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+0x1958/0x2c70 net/ipv4/udp.c:1022
 udpv6_sendmsg+0x743/0x3380 net/ipv6/udp.c:1185
 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
 ___sys_sendmsg+0x322/0x8a0 net/socket.c:2049
 __sys_sendmmsg+0x1e6/0x5f0 net/socket.c:2139
 SYSC_sendmmsg net/socket.c:2170 [inline]
 SyS_sendmmsg+0x35/0x60 net/socket.c:2165
 entry_SYSCALL_64_fastpath+0x1f/0xbe
RIP: 0033:0x435249
RSP: 002b:00007ffd9c7d8b48 EFLAGS: 00000217 ORIG_RAX: 0000000000000133
RAX: ffffffffffffffda RBX: 00000000004002b0 RCX: 0000000000435249
RDX: 0000000000000001 RSI: 0000000020498000 RDI: 0000000000000003
RBP: 0000000000000082 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000040004 R11: 0000000000000217 R12: 0000000000000000
R13: 0000000000401bc0 R14: 0000000000401c50 R15: 0000000000000000

The buggy address belongs to the page:
page:ffffea0001b143c0 count:0 mapcount:0 mapping:          (null) index:0x0
flags: 0x500000000000000()
raw: 0500000000000000 0000000000000000 0000000000000000 00000000ffffffff
raw: 0000000000000000 ffffea0001b143e0 0000000000000000 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88006c50f380: 00 00 00 00 00 00 00 00 00 f1 f1 f1 f1 00 f2 f2
 ffff88006c50f400: f2 f2 f2 f2 f2 f8 f2 f2 f2 f2 f2 f2 f2 00 00 00
>ffff88006c50f480: 00 f2 f2 f2 f2 00 00 00 00 00 00 00 f2 f2 f2 f2
                                                       ^
 ffff88006c50f500: f2 00 00 00 00 00 00 00 00 00 f2 f2 f2 f3 f3 f3
 ffff88006c50f580: f3 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
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