netlink: 17 bytes leftover after parsing attributes in process `syz-executor496'.
IPv6: IPV6: multipath route replace failed (check consistency of installed routes): :: nexthop :: ifi 1
IPv6: IPV6: multipath route replace failed (check consistency of installed routes): :: nexthop :: ifi 13
==================================================================
BUG: KASAN: use-after-free in ip6_route_mpath_notify+0xe9/0x100 net/ipv6/route.c:4180
Read of size 4 at addr ffff8801ad544cf0 by task syz-executor496/4499

CPU: 0 PID: 4499 Comm: syz-executor496 Not tainted 4.17.0-rc7+ #78
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_load4_noabort+0x14/0x20 mm/kasan/report.c:432
 ip6_route_mpath_notify+0xe9/0x100 net/ipv6/route.c:4180
 ip6_route_multipath_add+0x615/0x1910 net/ipv6/route.c:4303
 inet6_rtm_newroute+0xe3/0x160 net/ipv6/route.c:4391
 rtnetlink_rcv_msg+0x466/0xc10 net/core/rtnetlink.c:4646
 netlink_rcv_skb+0x172/0x440 net/netlink/af_netlink.c:2448
 rtnetlink_rcv+0x1c/0x20 net/core/rtnetlink.c:4664
 netlink_unicast_kernel net/netlink/af_netlink.c:1310 [inline]
 netlink_unicast+0x58b/0x740 net/netlink/af_netlink.c:1336
 netlink_sendmsg+0x9f0/0xfa0 net/netlink/af_netlink.c:1901
 sock_sendmsg_nosec net/socket.c:629 [inline]
 sock_sendmsg+0xd5/0x120 net/socket.c:639
 ___sys_sendmsg+0x805/0x940 net/socket.c:2117
 __sys_sendmsg+0x115/0x270 net/socket.c:2155
 __do_sys_sendmsg net/socket.c:2164 [inline]
 __se_sys_sendmsg net/socket.c:2162 [inline]
 __x64_sys_sendmsg+0x78/0xb0 net/socket.c:2162
 do_syscall_64+0x1b1/0x800 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x441809
RSP: 002b:00007ffd5baa6ec8 EFLAGS: 00000217 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000441809
RDX: 0000000000000000 RSI: 0000000020000080 RDI: 0000000000000004
RBP: 00000000006cd018 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000217 R12: 0000000000402500
R13: 0000000000402590 R14: 0000000000000000 R15: 0000000000000000

Allocated by task 4499:
 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:104
 __ip6_dst_alloc+0x35/0xa0 net/ipv6/route.c:361
 ip6_dst_alloc+0x29/0xb0 net/ipv6/route.c:376
 ip6_route_info_create+0x4d4/0x3a30 net/ipv6/route.c:2834
 ip6_route_multipath_add+0xc7e/0x1910 net/ipv6/route.c:4240
 inet6_rtm_newroute+0xe3/0x160 net/ipv6/route.c:4391
 rtnetlink_rcv_msg+0x466/0xc10 net/core/rtnetlink.c:4646
 netlink_rcv_skb+0x172/0x440 net/netlink/af_netlink.c:2448
 rtnetlink_rcv+0x1c/0x20 net/core/rtnetlink.c:4664
 netlink_unicast_kernel net/netlink/af_netlink.c:1310 [inline]
 netlink_unicast+0x58b/0x740 net/netlink/af_netlink.c:1336
 netlink_sendmsg+0x9f0/0xfa0 net/netlink/af_netlink.c:1901
 sock_sendmsg_nosec net/socket.c:629 [inline]
 sock_sendmsg+0xd5/0x120 net/socket.c:639
 ___sys_sendmsg+0x805/0x940 net/socket.c:2117
 __sys_sendmsg+0x115/0x270 net/socket.c:2155
 __do_sys_sendmsg net/socket.c:2164 [inline]
 __se_sys_sendmsg net/socket.c:2162 [inline]
 __x64_sys_sendmsg+0x78/0xb0 net/socket.c:2162
 do_syscall_64+0x1b1/0x800 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 4499:
 save_stack+0x43/0xd0 mm/kasan/kasan.c:448
 set_track mm/kasan/kasan.c:460 [inline]
 __kasan_slab_free+0x11a/0x170 mm/kasan/kasan.c:521
 kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528
 __cache_free mm/slab.c:3498 [inline]
 kmem_cache_free+0x86/0x2d0 mm/slab.c:3756
 dst_destroy+0x267/0x3c0 net/core/dst.c:140
 dst_release_immediate+0x71/0x9e net/core/dst.c:205
 fib6_add+0xa40/0x1650 net/ipv6/ip6_fib.c:1305
 __ip6_ins_rt+0x6c/0x90 net/ipv6/route.c:1011
 ip6_route_multipath_add+0x513/0x1910 net/ipv6/route.c:4267
 inet6_rtm_newroute+0xe3/0x160 net/ipv6/route.c:4391
 rtnetlink_rcv_msg+0x466/0xc10 net/core/rtnetlink.c:4646
 netlink_rcv_skb+0x172/0x440 net/netlink/af_netlink.c:2448
 rtnetlink_rcv+0x1c/0x20 net/core/rtnetlink.c:4664
 netlink_unicast_kernel net/netlink/af_netlink.c:1310 [inline]
 netlink_unicast+0x58b/0x740 net/netlink/af_netlink.c:1336
 netlink_sendmsg+0x9f0/0xfa0 net/netlink/af_netlink.c:1901
 sock_sendmsg_nosec net/socket.c:629 [inline]
 sock_sendmsg+0xd5/0x120 net/socket.c:639
 ___sys_sendmsg+0x805/0x940 net/socket.c:2117
 __sys_sendmsg+0x115/0x270 net/socket.c:2155
 __do_sys_sendmsg net/socket.c:2164 [inline]
 __se_sys_sendmsg net/socket.c:2162 [inline]
 __x64_sys_sendmsg+0x78/0xb0 net/socket.c:2162
 do_syscall_64+0x1b1/0x800 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

The buggy address belongs to the object at ffff8801ad544c40
 which belongs to the cache ip6_dst_cache of size 320
The buggy address is located 176 bytes inside of
 320-byte region [ffff8801ad544c40, ffff8801ad544d80)
The buggy address belongs to the page:
page:ffffea0006b55100 count:1 mapcount:0 mapping:ffff8801ad544040 index:0x0
flags: 0x2fffc0000000100(slab)
raw: 02fffc0000000100 ffff8801ad544040 0000000000000000 000000010000000a
raw: ffffea0006b461e0 ffff8801cda23b48 ffff8801cda1c180 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801ad544b80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8801ad544c00: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
>ffff8801ad544c80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                             ^
 ffff8801ad544d00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8801ad544d80: fc fc fc fc fc fc fc fc 00 00 00 00 00 00 00 00
==================================================================