==================================================================
BUG: KASAN: stack-out-of-bounds in xfrm_flowi_dport include/net/xfrm.h:902 [inline]
BUG: KASAN: stack-out-of-bounds in __xfrm6_selector_match net/xfrm/xfrm_policy.c:91 [inline]
BUG: KASAN: stack-out-of-bounds in xfrm_selector_match+0xd3b/0xe40 net/xfrm/xfrm_policy.c:104
Read of size 2 at addr ffff8800a7717664 by task syz-executor.0/17325

CPU: 0 PID: 17325 Comm: syz-executor.0 Not tainted 4.9.141+ #1
 ffff8800a7716c40 ffffffff81b42e79 ffffea00029dc5c0 ffff8800a7717664
 0000000000000000 ffff8800a7717664 0000000000000000 ffff8800a7716c78
 ffffffff815009b8 ffff8800a7717664 0000000000000002 0000000000000000
Call Trace:
 [<ffffffff81b42e79>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81b42e79>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff815009b8>] print_address_description+0x6c/0x234 mm/kasan/report.c:256
 [<ffffffff81500dc2>] kasan_report_error mm/kasan/report.c:355 [inline]
 [<ffffffff81500dc2>] kasan_report.cold.6+0x242/0x2fe mm/kasan/report.c:412
 [<ffffffff814f3034>] __asan_report_load2_noabort+0x14/0x20 mm/kasan/report.c:431
 [<ffffffff8263fdfb>] xfrm_flowi_dport include/net/xfrm.h:902 [inline]
 [<ffffffff8263fdfb>] __xfrm6_selector_match net/xfrm/xfrm_policy.c:91 [inline]
 [<ffffffff8263fdfb>] xfrm_selector_match+0xd3b/0xe40 net/xfrm/xfrm_policy.c:104
 [<ffffffff82654392>] xfrm_state_look_at.constprop.9+0x232/0x330 net/xfrm/xfrm_state.c:764
 [<ffffffff82655d1c>] xfrm_state_find+0x10cc/0x2920 net/xfrm/xfrm_state.c:835
 [<ffffffff8263cc82>] xfrm_tmpl_resolve_one+0x1d2/0x7a0 net/xfrm/xfrm_policy.c:1500
 [<ffffffff8263d46f>] xfrm_tmpl_resolve net/xfrm/xfrm_policy.c:1544 [inline]
 [<ffffffff8263d46f>] xfrm_resolve_and_create_bundle+0x21f/0x1e70 net/xfrm/xfrm_policy.c:1893
 [<ffffffff82640569>] xfrm_lookup+0x239/0xc00 net/xfrm/xfrm_policy.c:2254
 [<ffffffff82641dc9>] xfrm_lookup_route+0x39/0x140 net/xfrm/xfrm_policy.c:2379
 [<ffffffff8248c500>] ip_route_output_flow+0x90/0xa0 net/ipv4/route.c:2448
 [<ffffffff8256be69>] udp_sendmsg+0x13d9/0x1c60 net/ipv4/udp.c:1025
 [<ffffffff8270876d>] udpv6_sendmsg+0x127d/0x2430 net/ipv6/udp.c:1086
 [<ffffffff825952f3>] inet_sendmsg+0x203/0x4d0 net/ipv4/af_inet.c:770
 [<ffffffff822a063b>] sock_sendmsg_nosec net/socket.c:648 [inline]
 [<ffffffff822a063b>] sock_sendmsg+0xbb/0x110 net/socket.c:658
 [<ffffffff822a209a>] ___sys_sendmsg+0x47a/0x840 net/socket.c:1982
 [<ffffffff822a55a1>] __sys_sendmmsg+0x161/0x3d0 net/socket.c:2072
 [<ffffffff822a5845>] SYSC_sendmmsg net/socket.c:2103 [inline]
 [<ffffffff822a5845>] SyS_sendmmsg+0x35/0x60 net/socket.c:2098
 [<ffffffff810056ef>] do_syscall_64+0x19f/0x550 arch/x86/entry/common.c:285
 [<ffffffff82817893>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb

The buggy address belongs to the page:
page:ffffea00029dc5c0 count:0 mapcount:0 mapping:          (null) index:0x0
flags: 0x0()
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8800a7717500: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 f1
 ffff8800a7717580: f1 f1 f1 00 f2 f2 f2 f2 f2 f2 f2 00 00 00 00 f2
>ffff8800a7717600: f2 f2 f2 00 00 00 00 00 00 00 f2 f2 f2 f2 f2 00
                                                       ^
 ffff8800a7717680: 00 00 00 00 00 00 00 00 f2 f2 f2 00 00 00 00 00
 ffff8800a7717700: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
==================================================================