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BUG: KASAN: stack-out-of-bounds in xfrm_state_find+0x303d/0x3170 net/xfrm/xfrm_state.c:1042
Read of size 4 at addr ffff8801d291f6d0 by task syz-executor4/16801

CPU: 1 PID: 16801 Comm: syz-executor4 Not tainted 4.13.0-rc5+ #35
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+0x24e/0x340 mm/kasan/report.c:409
 __asan_report_load4_noabort+0x14/0x20 mm/kasan/report.c:429
 xfrm_state_find+0x303d/0x3170 net/xfrm/xfrm_state.c:1042
 xfrm_tmpl_resolve_one net/xfrm/xfrm_policy.c:1470 [inline]
 xfrm_tmpl_resolve+0x309/0xbf0 net/xfrm/xfrm_policy.c:1514
 xfrm_resolve_and_create_bundle+0x102/0x2080 net/xfrm/xfrm_policy.c:1855
 xfrm_lookup+0xd39/0x11c0 net/xfrm/xfrm_policy.c:2216
 xfrm_lookup_route+0x39/0x1a0 net/xfrm/xfrm_policy.c:2337
 ip_route_output_flow+0x7c/0xa0 net/ipv4/route.c:2543
 udp_sendmsg+0x1958/0x2c70 net/ipv4/udp.c:1015
 udpv6_sendmsg+0x735/0x31a0 net/ipv6/udp.c:1171
 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
 sock_write_iter+0x31a/0x5d0 net/socket.c:898
 call_write_iter include/linux/fs.h:1743 [inline]
 new_sync_write fs/read_write.c:457 [inline]
 __vfs_write+0x684/0x970 fs/read_write.c:470
 vfs_write+0x189/0x510 fs/read_write.c:518
 SYSC_write fs/read_write.c:565 [inline]
 SyS_write+0xef/0x220 fs/read_write.c:557
 entry_SYSCALL_64_fastpath+0x1f/0xbe
RIP: 0033:0x4512e9
RSP: 002b:00007fa32d603c08 EFLAGS: 00000216 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00000000007180a8 RCX: 00000000004512e9
RDX: 00000000000000b3 RSI: 00000000205f5f4d RDI: 0000000000000005
RBP: 0000000000000086 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000216 R12: 00000000004b70fd
R13: 00000000ffffffff R14: 0000000020000000 R15: 0000000000fff000

The buggy address belongs to the page:
page:ffffea00074a47c0 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:
 ffff8801d291f580: 00 00 00 00 00 00 00 f1 f1 f1 f1 00 f2 f2 f2 f2
 ffff8801d291f600: f2 f2 f2 f8 f2 f2 f2 f2 f2 f2 f2 00 00 00 00 f2
>ffff8801d291f680: f2 f2 f2 00 00 00 00 00 00 00 f2 f2 f2 f2 f2 00
                                                 ^
 ffff8801d291f700: 00 00 00 00 00 00 00 00 f2 f2 f2 f3 f3 f3 f3 00
 ffff8801d291f780: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
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