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BUG: KASAN: stack-out-of-bounds in xfrm_state_find+0x2453/0x2830 net/xfrm/xfrm_state.c:822
Read of size 4 at addr ffff8801ca3878b0 by task syzkaller949618/3307

CPU: 0 PID: 3307 Comm: syzkaller949618 Not tainted 4.9.71-g2506378 #113
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 ffff8801ca386f00 ffffffff81d922b9 ffffea000728e1c0 ffff8801ca3878b0
 0000000000000000 ffff8801ca3878b0 ffff8801d035afa0 ffff8801ca386f38
 ffffffff8153bab3 ffff8801ca3878b0 0000000000000004 0000000000000000
Call Trace:
 [<ffffffff81d922b9>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81d922b9>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff8153bab3>] print_address_description+0x73/0x280 mm/kasan/report.c:252
 [<ffffffff8153bfd5>] kasan_report_error mm/kasan/report.c:351 [inline]
 [<ffffffff8153bfd5>] kasan_report+0x275/0x360 mm/kasan/report.c:408
 [<ffffffff8153c114>] __asan_report_load4_noabort+0x14/0x20 mm/kasan/report.c:428
 [<ffffffff833d6853>] xfrm_state_find+0x2453/0x2830 net/xfrm/xfrm_state.c:822
 [<ffffffff833bbae8>] xfrm_tmpl_resolve_one net/xfrm/xfrm_policy.c:1476 [inline]
 [<ffffffff833bbae8>] xfrm_tmpl_resolve+0x298/0xa90 net/xfrm/xfrm_policy.c:1520
 [<ffffffff833bc3b7>] xfrm_resolve_and_create_bundle+0xd7/0x1d90 net/xfrm/xfrm_policy.c:1868
 [<ffffffff833c1c74>] xfrm_lookup+0x984/0xbf0 net/xfrm/xfrm_policy.c:2222
 [<ffffffff833c2dd9>] xfrm_lookup_route+0x39/0x1a0 net/xfrm/xfrm_policy.c:2344
 [<ffffffff831dcabf>] ip_route_output_flow+0x7f/0xa0 net/ipv4/route.c:2435
 [<ffffffff832b9e76>] udp_sendmsg+0xe36/0x1c10 net/ipv4/udp.c:1023
 [<ffffffff8348a808>] udpv6_sendmsg+0x588/0x2540 net/ipv6/udp.c:1086
 [<ffffffff832ed53c>] inet_sendmsg+0x2bc/0x4c0 net/ipv4/af_inet.c:770
 [<ffffffff82ed4baa>] sock_sendmsg_nosec net/socket.c:635 [inline]
 [<ffffffff82ed4baa>] sock_sendmsg+0xca/0x110 net/socket.c:645
 [<ffffffff82ed5b08>] SYSC_sendto+0x2c8/0x340 net/socket.c:1670
 [<ffffffff82ed7ff0>] SyS_sendto+0x40/0x50 net/socket.c:1638
 [<ffffffff838aef85>] entry_SYSCALL_64_fastpath+0x23/0xc6

The buggy address belongs to the page:
page:ffffea000728e1c0 count:0 mapcount:0 mapping:          (null) index:0x0
flags: 0x8000000000000000()
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801ca387780: 00 00 00 00 00 00 00 00 00 00 00 f1 f1 f1 f1 00
 ffff8801ca387800: f2 f2 f2 f2 f2 f2 f2 00 00 00 00 f2 f2 f2 f2 00
>ffff8801ca387880: 00 00 00 00 00 00 f2 f2 f2 f2 f2 00 00 00 00 00
                                     ^
 ffff8801ca387900: 00 00 00 00 f2 f2 f2 00 00 00 00 00 00 00 00 00
 ffff8801ca387980: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
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