================================================================== BUG: KASAN: slab-out-of-bounds in __ipv6_addr_type+0x26c/0x290 net/ipv6/addrconf_core.c:68 Read of size 4 at addr ffff8800a4fefd38 by task syz-executor.2/2534 CPU: 0 PID: 2534 Comm: syz-executor.2 Not tainted 4.4.174+ #4 0000000000000000 c748c075853837b1 ffff8800a6b66da0 ffffffff81aad1a1 0000000000000000 ffffea000293fb00 ffff8800a4fefd38 0000000000000004 ffff8800a4fefa80 ffff8800a6b66dd8 ffffffff81490120 0000000000000000 Call Trace: [] __dump_stack lib/dump_stack.c:15 [inline] [] dump_stack+0xc1/0x120 lib/dump_stack.c:51 [] print_address_description+0x6f/0x21b mm/kasan/report.c:252 [] kasan_report_error mm/kasan/report.c:351 [inline] [] kasan_report mm/kasan/report.c:408 [inline] [] kasan_report.cold+0x8c/0x2be mm/kasan/report.c:393 [] __asan_report_load4_noabort+0x14/0x20 mm/kasan/report.c:428 [] __ipv6_addr_type+0x26c/0x290 net/ipv6/addrconf_core.c:68 [] ipv6_addr_type include/net/ipv6.h:330 [inline] [] ip6_tnl_xmit2+0x2ac/0x2320 net/ipv6/ip6_tunnel.c:988 [] ip4ip6_tnl_xmit net/ipv6/ip6_tunnel.c:1134 [inline] [] ip6_tnl_xmit+0xa09/0xe00 net/ipv6/ip6_tunnel.c:1212 [] __netdev_start_xmit include/linux/netdevice.h:3750 [inline] [] netdev_start_xmit include/linux/netdevice.h:3759 [inline] [] xmit_one net/core/dev.c:2781 [inline] [] dev_hard_start_xmit+0x7c1/0x11e0 net/core/dev.c:2797 [] __dev_queue_xmit+0x164b/0x1bb0 net/core/dev.c:3229 [] dev_queue_xmit+0x18/0x20 net/core/dev.c:3263 [] neigh_direct_output+0x16/0x20 net/core/neighbour.c:1369 [] dst_neigh_output include/net/dst.h:461 [inline] [] ip_finish_output2+0x6a2/0x1280 net/ipv4/ip_output.c:213 [] ip_finish_output+0x8b2/0xc60 net/ipv4/ip_output.c:288 [] NF_HOOK_COND include/linux/netfilter.h:240 [inline] [] ip_output+0x227/0x4c0 net/ipv4/ip_output.c:362 [] dst_output include/net/dst.h:498 [inline] [] ip_local_out+0x9c/0x180 net/ipv4/ip_output.c:119 [] ip_send_skb+0x3e/0xc0 net/ipv4/ip_output.c:1453 [] udp_send_skb+0x4fd/0xc70 net/ipv4/udp.c:842 [] udp_sendmsg+0x16cf/0x1c60 net/ipv4/udp.c:1072 [] udpv6_sendmsg+0x12f2/0x24f0 net/ipv6/udp.c:1173 [] inet_sendmsg+0x202/0x4d0 net/ipv4/af_inet.c:755 [] sock_sendmsg_nosec net/socket.c:638 [inline] [] sock_sendmsg+0xbe/0x110 net/socket.c:648 [] ___sys_sendmsg+0x769/0x890 net/socket.c:1975 [] __sys_sendmsg+0xc5/0x160 net/socket.c:2009 [] SYSC_sendmsg net/socket.c:2020 [inline] [] SyS_sendmsg+0x2d/0x50 net/socket.c:2016 [] entry_SYSCALL_64_fastpath+0x1e/0x9a Allocated by task 2534: [] save_stack_trace+0x26/0x50 arch/x86/kernel/stacktrace.c:63 [] save_stack mm/kasan/kasan.c:512 [inline] [] set_track mm/kasan/kasan.c:524 [inline] [] kasan_kmalloc.part.0+0x62/0xf0 mm/kasan/kasan.c:616 [] kasan_kmalloc+0xb7/0xd0 mm/kasan/kasan.c:601 [] __kmalloc+0x141/0x330 mm/slub.c:3613 [] kmalloc include/linux/slab.h:481 [inline] [] kzalloc include/linux/slab.h:620 [inline] [] neigh_alloc net/core/neighbour.c:285 [inline] [] __neigh_create+0x1d6/0x1b30 net/core/neighbour.c:457 [] neigh_create include/net/neighbour.h:313 [inline] [] ipv4_neigh_lookup+0x52e/0x6e0 net/ipv4/route.c:464 [] dst_neigh_lookup include/net/dst.h:466 [inline] [] ip6_tnl_xmit2+0x27b/0x2320 net/ipv6/ip6_tunnel.c:982 [] ip4ip6_tnl_xmit net/ipv6/ip6_tunnel.c:1134 [inline] [] ip6_tnl_xmit+0xa09/0xe00 net/ipv6/ip6_tunnel.c:1212 [] __netdev_start_xmit include/linux/netdevice.h:3750 [inline] [] netdev_start_xmit include/linux/netdevice.h:3759 [inline] [] xmit_one net/core/dev.c:2781 [inline] [] dev_hard_start_xmit+0x7c1/0x11e0 net/core/dev.c:2797 [] __dev_queue_xmit+0x164b/0x1bb0 net/core/dev.c:3229 [] dev_queue_xmit+0x18/0x20 net/core/dev.c:3263 [] neigh_direct_output+0x16/0x20 net/core/neighbour.c:1369 [] dst_neigh_output include/net/dst.h:461 [inline] [] ip_finish_output2+0x6a2/0x1280 net/ipv4/ip_output.c:213 [] ip_finish_output+0x8b2/0xc60 net/ipv4/ip_output.c:288 [] NF_HOOK_COND include/linux/netfilter.h:240 [inline] [] ip_output+0x227/0x4c0 net/ipv4/ip_output.c:362 [] dst_output include/net/dst.h:498 [inline] [] ip_local_out+0x9c/0x180 net/ipv4/ip_output.c:119 [] ip_send_skb+0x3e/0xc0 net/ipv4/ip_output.c:1453 [] udp_send_skb+0x4fd/0xc70 net/ipv4/udp.c:842 [] udp_sendmsg+0x16cf/0x1c60 net/ipv4/udp.c:1072 [] udpv6_sendmsg+0x12f2/0x24f0 net/ipv6/udp.c:1173 [] inet_sendmsg+0x202/0x4d0 net/ipv4/af_inet.c:755 [] sock_sendmsg_nosec net/socket.c:638 [inline] [] sock_sendmsg+0xbe/0x110 net/socket.c:648 [] ___sys_sendmsg+0x769/0x890 net/socket.c:1975 [] __sys_sendmsg+0xc5/0x160 net/socket.c:2009 [] SYSC_sendmsg net/socket.c:2020 [inline] [] SyS_sendmsg+0x2d/0x50 net/socket.c:2016 [] entry_SYSCALL_64_fastpath+0x1e/0x9a Freed by task 996: [] save_stack_trace+0x26/0x50 arch/x86/kernel/stacktrace.c:63 [] save_stack mm/kasan/kasan.c:512 [inline] [] set_track mm/kasan/kasan.c:524 [inline] [] kasan_slab_free+0xb0/0x190 mm/kasan/kasan.c:589 [] slab_free_hook mm/slub.c:1383 [inline] [] slab_free_freelist_hook mm/slub.c:1405 [inline] [] slab_free mm/slub.c:2859 [inline] [] kfree+0xf4/0x310 mm/slub.c:3749 [] skb_free_head net/core/skbuff.c:571 [inline] [] skb_release_data+0x2e6/0x380 net/core/skbuff.c:602 [] skb_release_all+0x4d/0x60 net/core/skbuff.c:661 [] __kfree_skb net/core/skbuff.c:675 [inline] [] kfree_skb+0xf7/0x400 net/core/skbuff.c:696 [] ipip6_tunnel_xmit net/ipv6/sit.c:998 [inline] [] sit_tunnel_xmit+0xfdb/0x2610 net/ipv6/sit.c:1030 [] __netdev_start_xmit include/linux/netdevice.h:3750 [inline] [] netdev_start_xmit include/linux/netdevice.h:3759 [inline] [] xmit_one net/core/dev.c:2781 [inline] [] dev_hard_start_xmit+0x7c1/0x11e0 net/core/dev.c:2797 [] __dev_queue_xmit+0x164b/0x1bb0 net/core/dev.c:3229 [] dev_queue_xmit+0x18/0x20 net/core/dev.c:3263 [] neigh_direct_output+0x16/0x20 net/core/neighbour.c:1369 [] dst_neigh_output include/net/dst.h:461 [inline] [] ip6_finish_output2+0x9c7/0x1dc0 net/ipv6/ip6_output.c:113 [] ip6_finish_output+0x2f3/0x750 net/ipv6/ip6_output.c:131 [] NF_HOOK_COND include/linux/netfilter.h:240 [inline] [] ip6_output+0x1b4/0x520 net/ipv6/ip6_output.c:145 [] dst_output include/net/dst.h:498 [inline] [] ip6_local_out+0x9c/0x180 net/ipv6/output_core.c:169 [] ip6_send_skb+0xa2/0x340 net/ipv6/ip6_output.c:1725 [] udp_v6_send_skb+0x85c/0xe90 net/ipv6/udp.c:1066 [] udpv6_sendmsg+0x1e3d/0x24f0 net/ipv6/udp.c:1330 [] inet_sendmsg+0x202/0x4d0 net/ipv4/af_inet.c:755 [] sock_sendmsg_nosec net/socket.c:638 [inline] [] sock_sendmsg+0xbe/0x110 net/socket.c:648 [] ___sys_sendmsg+0x369/0x890 net/socket.c:1975 [] __sys_sendmmsg+0x130/0x2e0 net/socket.c:2060 [] SYSC_sendmmsg net/socket.c:2090 [inline] [] SyS_sendmmsg+0x35/0x60 net/socket.c:2085 [] entry_SYSCALL_64_fastpath+0x1e/0x9a The buggy address belongs to the object at ffff8800a4fefa80 which belongs to the cache kmalloc-1024 of size 1024 The buggy address is located 696 bytes inside of 1024-byte region [ffff8800a4fefa80, ffff8800a4fefe80) The buggy address belongs to the page: audit: type=1400 audit(1559652097.754:391): avc: denied { sigchld } for pid=2138 comm="syz-executor.3" scontext=system_u:object_r:unlabeled_t:s0 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=process permissive=0 ------------[ cut here ]------------ WARNING: CPU: 1 PID: 2138 at lib/list_debug.c:51 __list_del_entry_valid+0x11d/0x1a0 lib/list_debug.c:51() list_del corruption. prev->next should be ffff8800a6b67f20, but was ff12c45be8c48949