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BUG: KASAN: stack-out-of-bounds in strlcpy include/linux/string.h:300 [inline]
BUG: KASAN: stack-out-of-bounds in ipip6_tunnel_locate+0x63b/0xaa0 net/ipv6/sit.c:254
Write of size 33 at addr ffff88018d6cf6d8 by task syz-executor6/23005

CPU: 1 PID: 23005 Comm: syz-executor6 Not tainted 4.16.0+ #16
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1b9/0x294 lib/dump_stack.c:113
 print_address_description+0x6c/0x20b mm/kasan/report.c:256
 kasan_report_error mm/kasan/report.c:354 [inline]
 kasan_report.cold.7+0xac/0x2f5 mm/kasan/report.c:412
 check_memory_region_inline mm/kasan/kasan.c:260 [inline]
 check_memory_region+0x13e/0x1b0 mm/kasan/kasan.c:267
 memcpy+0x37/0x50 mm/kasan/kasan.c:303
 strlcpy include/linux/string.h:300 [inline]
 ipip6_tunnel_locate+0x63b/0xaa0 net/ipv6/sit.c:254
 ipip6_tunnel_ioctl+0xe71/0x241b net/ipv6/sit.c:1221
 dev_ifsioc+0x43e/0xb90 net/core/dev_ioctl.c:334
 dev_ioctl+0x69a/0xcc0 net/core/dev_ioctl.c:525
 sock_ioctl+0x47e/0x680 net/socket.c:1015
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:500 [inline]
 do_vfs_ioctl+0x1cf/0x1650 fs/ioctl.c:684
 ksys_ioctl+0xa9/0xd0 fs/ioctl.c:701
 SYSC_ioctl fs/ioctl.c:708 [inline]
 SyS_ioctl+0x24/0x30 fs/ioctl.c:706
 do_syscall_64+0x29e/0x9d0 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x455259
RSP: 002b:00007f5ef1ed6c68 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f5ef1ed76d4 RCX: 0000000000455259
RDX: 00000000200001c0 RSI: 00000000000089f1 RDI: 0000000000000014
RBP: 000000000072bea0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 0000000000000381 R14: 00000000006f84b8 R15: 0000000000000000

The buggy address belongs to the page:
page:ffffea000635b3c0 count:0 mapcount:0 mapping:0000000000000000 index:0x0
flags: 0x2fffc0000000000()
raw: 02fffc0000000000 0000000000000000 0000000000000000 00000000ffffffff
raw: dead000000000100 dead000000000200 0000000000000000 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88018d6cf580: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88018d6cf600: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 f1
>ffff88018d6cf680: f1 f1 f1 f8 f2 f2 f2 f2 f2 f2 f2 00 00 f2 f2 00
                                                          ^
 ffff88018d6cf700: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88018d6cf780: 00 00 f1 f1 f1 f1 f8 f2 f2 f2 f2 f2 f2 f2 00 f2
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