netlink: 17 bytes leftover after parsing attributes in process `syz-executor2'. 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+0xda/0xf0 net/ipv6/route.c:4328 Read of size 4 at addr ffff8801d8c25d28 by task syz-executor2/29614 CPU: 0 PID: 29614 Comm: syz-executor2 Not tainted 4.17.0-rc7+ #76 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+0xda/0xf0 net/ipv6/route.c:4328 ip6_route_multipath_add+0x67a/0x1a50 net/ipv6/route.c:4455 inet6_rtm_newroute+0xe3/0x160 net/ipv6/route.c:4542 rtnetlink_rcv_msg+0x466/0xc10 net/core/rtnetlink.c:4662 netlink_rcv_skb+0x172/0x440 net/netlink/af_netlink.c:2448 rtnetlink_rcv+0x1c/0x20 net/core/rtnetlink.c:4680 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: 0033:0x455a09 RSP: 002b:00007f2489a40c68 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007f2489a416d4 RCX: 0000000000455a09 RDX: 0000000000000000 RSI: 0000000020000080 RDI: 0000000000000013 RBP: 000000000072bea0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000000005ab R14: 00000000006fd8a8 R15: 0000000000000000 Allocated by task 29614: 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 kmem_cache_alloc_trace+0x152/0x780 mm/slab.c:3620 kmalloc include/linux/slab.h:512 [inline] kzalloc include/linux/slab.h:701 [inline] fib6_info_alloc+0xbb/0x280 net/ipv6/ip6_fib.c:152 ip6_route_info_create+0x782/0x2c00 net/ipv6/route.c:3013 ip6_route_multipath_add+0xccb/0x1a50 net/ipv6/route.c:4388 inet6_rtm_newroute+0xe3/0x160 net/ipv6/route.c:4542 rtnetlink_rcv_msg+0x466/0xc10 net/core/rtnetlink.c:4662 netlink_rcv_skb+0x172/0x440 net/netlink/af_netlink.c:2448 rtnetlink_rcv+0x1c/0x20 net/core/rtnetlink.c:4680 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 29614: 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] kfree+0xd9/0x260 mm/slab.c:3813 fib6_info_destroy+0x29b/0x350 net/ipv6/ip6_fib.c:207 fib6_info_release include/net/ip6_fib.h:286 [inline] ip6_route_multipath_add+0x9dd/0x1a50 net/ipv6/route.c:4417 inet6_rtm_newroute+0xe3/0x160 net/ipv6/route.c:4542 rtnetlink_rcv_msg+0x466/0xc10 net/core/rtnetlink.c:4662 netlink_rcv_skb+0x172/0x440 net/netlink/af_netlink.c:2448 rtnetlink_rcv+0x1c/0x20 net/core/rtnetlink.c:4680 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 ffff8801d8c25d00 which belongs to the cache kmalloc-256 of size 256 The buggy address is located 40 bytes inside of 256-byte region [ffff8801d8c25d00, ffff8801d8c25e00) The buggy address belongs to the page: page:ffffea0007630940 count:1 mapcount:0 mapping:ffff8801d8c25080 index:0xffff8801d8c256c0 flags: 0x2fffc0000000100(slab) raw: 02fffc0000000100 ffff8801d8c25080 ffff8801d8c256c0 000000010000000b raw: ffffea0007609ee0 ffffea0007372c60 ffff8801da8007c0 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8801d8c25c00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff8801d8c25c80: 00 00 00 00 00 00 00 06 fc fc fc fc fc fc fc fc >ffff8801d8c25d00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8801d8c25d80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8801d8c25e00: fc fc fc fc fc fc fc fc 00 00 00 00 00 00 00 00 ==================================================================