================================================================== BUG: KASAN: use-after-free in rtnetlink_put_metrics+0x621/0x690 net/core/rtnetlink.c:754 Read of size 4 at addr ffff8801d7b2fa80 by task syz-executor2/15614 CPU: 0 PID: 15614 Comm: syz-executor2 Not tainted 4.18.0-rc7+ #74 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+0x1c9/0x2b4 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 rtnetlink_put_metrics+0x621/0x690 net/core/rtnetlink.c:754 rt6_fill_node+0x7d9/0x1540 net/ipv6/route.c:4753 inet6_rt_notify+0x161/0x2c0 net/ipv6/route.c:4985 fib6_del_route net/ipv6/ip6_fib.c:1788 [inline] fib6_del+0xf4d/0x1310 net/ipv6/ip6_fib.c:1815 __ip6_del_rt_siblings net/ipv6/route.c:3244 [inline] ip6_route_del+0x1094/0x14e0 net/ipv6/route.c:3330 ipv6_route_ioctl+0x616/0x760 net/ipv6/route.c:3681 inet6_ioctl+0x100/0x1f0 net/ipv6/af_inet6.c:546 sock_do_ioctl+0xe4/0x3e0 net/socket.c:970 routing_ioctl+0x3cb/0x880 net/socket.c:3088 compat_sock_ioctl_trans net/socket.c:3135 [inline] compat_sock_ioctl+0xbe3/0x1f90 net/socket.c:3226 __do_compat_sys_ioctl fs/compat_ioctl.c:1459 [inline] __se_compat_sys_ioctl fs/compat_ioctl.c:1405 [inline] __ia32_compat_sys_ioctl+0x221/0x640 fs/compat_ioctl.c:1405 do_syscall_32_irqs_on arch/x86/entry/common.c:326 [inline] do_fast_syscall_32+0x34d/0xfb2 arch/x86/entry/common.c:397 entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139 RIP: 0023:0xf7f6dcb9 Code: 55 08 8b 88 64 cd ff ff 8b 98 68 cd ff ff 89 c8 85 d2 74 02 89 0a 5b 5d c3 8b 04 24 c3 8b 1c 24 c3 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 eb 0d 90 90 90 90 90 90 90 90 90 90 90 90 RSP: 002b:00000000f5f690cc EFLAGS: 00000296 ORIG_RAX: 0000000000000036 RAX: ffffffffffffffda RBX: 0000000000000013 RCX: 000000000000890c RDX: 0000000020000180 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 Allocated by task 1012: 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:513 [inline] kzalloc include/linux/slab.h:707 [inline] fib6_metric_set+0x163/0x2c0 net/ipv6/ip6_fib.c:645 fib6_add_rt2node+0xe36/0x27f0 net/ipv6/ip6_fib.c:1000 fib6_add+0xaae/0x14d0 net/ipv6/ip6_fib.c:1308 __ip6_ins_rt+0x54/0x80 net/ipv6/route.c:1163 ip6_route_add+0x6d/0xc0 net/ipv6/route.c:3171 addrconf_prefix_route.isra.48+0x51d/0x720 net/ipv6/addrconf.c:2347 inet6_addr_modify net/ipv6/addrconf.c:4627 [inline] inet6_rtm_newaddr+0x112e/0x1b50 net/ipv6/addrconf.c:4743 rtnetlink_rcv_msg+0x46e/0xc30 net/core/rtnetlink.c:4665 netlink_rcv_skb+0x172/0x440 net/netlink/af_netlink.c:2453 rtnetlink_rcv+0x1c/0x20 net/core/rtnetlink.c:4683 netlink_unicast_kernel net/netlink/af_netlink.c:1315 [inline] netlink_unicast+0x5a0/0x760 net/netlink/af_netlink.c:1341 netlink_sendmsg+0xa18/0xfd0 net/netlink/af_netlink.c:1906 sock_sendmsg_nosec net/socket.c:642 [inline] sock_sendmsg+0xd5/0x120 net/socket.c:652 ___sys_sendmsg+0x7fd/0x930 net/socket.c:2126 __sys_sendmsg+0x11d/0x290 net/socket.c:2164 __compat_sys_sendmsg net/compat.c:756 [inline] __do_compat_sys_sendmsg net/compat.c:763 [inline] __se_compat_sys_sendmsg net/compat.c:760 [inline] __ia32_compat_sys_sendmsg+0x7a/0xb0 net/compat.c:760 do_syscall_32_irqs_on arch/x86/entry/common.c:326 [inline] do_fast_syscall_32+0x34d/0xfb2 arch/x86/entry/common.c:397 entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139 Freed by task 15614: 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_metrics_release+0x77/0x90 net/ipv6/ip6_fib.c:179 fib6_drop_pcpu_from net/ipv6/ip6_fib.c:899 [inline] fib6_purge_rt+0x5ec/0x7f0 net/ipv6/ip6_fib.c:934 fib6_del_route net/ipv6/ip6_fib.c:1784 [inline] fib6_del+0xc11/0x1310 net/ipv6/ip6_fib.c:1815 __ip6_del_rt_siblings net/ipv6/route.c:3244 [inline] ip6_route_del+0x1094/0x14e0 net/ipv6/route.c:3330 ipv6_route_ioctl+0x616/0x760 net/ipv6/route.c:3681 inet6_ioctl+0x100/0x1f0 net/ipv6/af_inet6.c:546 sock_do_ioctl+0xe4/0x3e0 net/socket.c:970 routing_ioctl+0x3cb/0x880 net/socket.c:3088 compat_sock_ioctl_trans net/socket.c:3135 [inline] compat_sock_ioctl+0xbe3/0x1f90 net/socket.c:3226 __do_compat_sys_ioctl fs/compat_ioctl.c:1459 [inline] __se_compat_sys_ioctl fs/compat_ioctl.c:1405 [inline] __ia32_compat_sys_ioctl+0x221/0x640 fs/compat_ioctl.c:1405 do_syscall_32_irqs_on arch/x86/entry/common.c:326 [inline] do_fast_syscall_32+0x34d/0xfb2 arch/x86/entry/common.c:397 entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139 The buggy address belongs to the object at ffff8801d7b2fa80 which belongs to the cache kmalloc-96 of size 96 The buggy address is located 0 bytes inside of 96-byte region [ffff8801d7b2fa80, ffff8801d7b2fae0) The buggy address belongs to the page: page:ffffea00075ecbc0 count:1 mapcount:0 mapping:ffff8801dac004c0 index:0x0 flags: 0x2fffc0000000100(slab) raw: 02fffc0000000100 ffffea00071ea448 ffffea00075b6688 ffff8801dac004c0 raw: 0000000000000000 ffff8801d7b2f000 0000000100000020 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8801d7b2f980: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc ffff8801d7b2fa00: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc >ffff8801d7b2fa80: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc ^ ffff8801d7b2fb00: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc ffff8801d7b2fb80: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc ==================================================================