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BUG: KASAN: slab-out-of-bounds in ip6_dst_idev include/net/ip6_fib.h:203 [inline]
BUG: KASAN: slab-out-of-bounds in ip6_xmit+0x2002/0x23f0 net/ipv6/ip6_output.c:264
Read of size 8 at addr ffff8801a0b02bb0 by task syz-executor7/16290

CPU: 0 PID: 16290 Comm: syz-executor7 Not tainted 4.17.0+ #39
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+0x242/0x2fe mm/kasan/report.c:412
 __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:433
 ip6_dst_idev include/net/ip6_fib.h:203 [inline]
 ip6_xmit+0x2002/0x23f0 net/ipv6/ip6_output.c:264
 inet6_csk_xmit+0x377/0x630 net/ipv6/inet6_connection_sock.c:139
 tcp_transmit_skb+0x1bea/0x3ec0 net/ipv4/tcp_output.c:1168
 tcp_send_syn_data net/ipv4/tcp_output.c:3453 [inline]
 tcp_connect+0x220f/0x45b0 net/ipv4/tcp_output.c:3492
 tcp_v4_connect+0x1934/0x1d50 net/ipv4/tcp_ipv4.c:301
 __inet_stream_connect+0x943/0x1120 net/ipv4/af_inet.c:655
 tcp_sendmsg_fastopen net/ipv4/tcp.c:1151 [inline]
 tcp_sendmsg_locked+0x2859/0x3ee0 net/ipv4/tcp.c:1198
 tcp_sendmsg+0x2f/0x50 net/ipv4/tcp.c:1436
 inet_sendmsg+0x19f/0x690 net/ipv4/af_inet.c:798
 sock_sendmsg_nosec net/socket.c:645 [inline]
 sock_sendmsg+0xd5/0x120 net/socket.c:655
 ___sys_sendmsg+0x805/0x940 net/socket.c:2161
 __sys_sendmsg+0x115/0x270 net/socket.c:2199
 __do_sys_sendmsg net/socket.c:2208 [inline]
 __se_sys_sendmsg net/socket.c:2206 [inline]
 __x64_sys_sendmsg+0x78/0xb0 net/socket.c:2206
 do_syscall_64+0x1b1/0x800 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x455b29
Code: 1d ba fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 eb b9 fb ff c3 66 2e 0f 1f 84 00 00 00 00 
RSP: 002b:00007fad349c0c68 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007fad349c16d4 RCX: 0000000000455b29
RDX: 0000000024008000 RSI: 0000000020000cc0 RDI: 0000000000000013
RBP: 000000000072bf50 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000004c0b1f R14: 00000000004d0510 R15: 0000000000000001

Allocated by task 9939:
 save_stack+0x43/0xd0 mm/kasan/kasan.c:448
 set_track mm/kasan/kasan.c:460 [inline]
 kasan_kmalloc+0xc4/0xe0 mm/kasan/kasan.c:553
 kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:490
 kmem_cache_alloc+0x12e/0x760 mm/slab.c:3554
 dst_alloc+0xbb/0x1d0 net/core/dst.c:105
 rt_dst_alloc+0xfa/0x500 net/ipv4/route.c:1576
 __mkroute_output net/ipv4/route.c:2271 [inline]
 ip_route_output_key_hash_rcu+0xa45/0x3380 net/ipv4/route.c:2498
 ip_route_output_key_hash+0x23a/0x390 net/ipv4/route.c:2327
 __ip_route_output_key include/net/route.h:124 [inline]
 ip_route_output_flow+0x28/0xc0 net/ipv4/route.c:2582
 ip_route_connect include/net/route.h:310 [inline]
 tcp_v4_connect+0x7f1/0x1d50 net/ipv4/tcp_ipv4.c:219
 tcp_v6_connect+0x8fb/0x2970 net/ipv6/tcp_ipv6.c:238
 __inet_stream_connect+0x943/0x1120 net/ipv4/af_inet.c:655
 tcp_sendmsg_fastopen net/ipv4/tcp.c:1151 [inline]
 tcp_sendmsg_locked+0x2859/0x3ee0 net/ipv4/tcp.c:1198
 tcp_sendmsg+0x2f/0x50 net/ipv4/tcp.c:1436
 inet_sendmsg+0x19f/0x690 net/ipv4/af_inet.c:798
 sock_sendmsg_nosec net/socket.c:645 [inline]
 sock_sendmsg+0xd5/0x120 net/socket.c:655
 ___sys_sendmsg+0x805/0x940 net/socket.c:2161
 __sys_sendmsg+0x115/0x270 net/socket.c:2199
 __do_sys_sendmsg net/socket.c:2208 [inline]
 __se_sys_sendmsg net/socket.c:2206 [inline]
 __x64_sys_sendmsg+0x78/0xb0 net/socket.c:2206
 do_syscall_64+0x1b1/0x800 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 0:
(stack is not available)

The buggy address belongs to the object at ffff8801a0b02b00
 which belongs to the cache ip_dst_cache of size 160
The buggy address is located 16 bytes to the right of
 160-byte region [ffff8801a0b02b00, ffff8801a0b02ba0)
The buggy address belongs to the page:
page:ffffea000682c080 count:1 mapcount:0 mapping:ffff8801d678f200 index:0xffff8801a0b02000
flags: 0x2fffc0000000100(slab)
raw: 02fffc0000000100 ffff8801d4446438 ffffea00066c53c8 ffff8801d678f200
raw: ffff8801a0b02000 ffff8801a0b02000 0000000100000004 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801a0b02a80: fb fb fb fb fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8801a0b02b00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff8801a0b02b80: 00 00 00 00 fc fc fc fc fc fc fc fc fc fc fc fc
                                     ^
 ffff8801a0b02c00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8801a0b02c80: fb fb fb fb fc fc fc fc fc fc fc fc fc fc fc fc
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