================================================================== BUG: KASAN: use-after-free in __list_add_valid+0x8f/0xac lib/list_debug.c:26 Read of size 8 at addr ffff8881997e6b70 by task syz-executor4/11937 CPU: 1 PID: 11937 Comm: syz-executor4 Not tainted 4.20.0-rc6+ #336 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+0x244/0x39d lib/dump_stack.c:113 print_address_description.cold.7+0x9/0x1ff mm/kasan/report.c:256 kasan_report_error mm/kasan/report.c:354 [inline] kasan_report.cold.8+0x242/0x309 mm/kasan/report.c:412 __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:433 __list_add_valid+0x8f/0xac lib/list_debug.c:26 __list_add include/linux/list.h:60 [inline] list_add_tail include/linux/list.h:93 [inline] neigh_alloc net/core/neighbour.c:395 [inline] ___neigh_create+0x14b7/0x2600 net/core/neighbour.c:553 __neigh_create+0x30/0x40 net/core/neighbour.c:640 ip_finish_output2+0xb91/0x1a30 net/ipv4/ip_output.c:224 ip_finish_output+0x7fd/0xfa0 net/ipv4/ip_output.c:317 NF_HOOK_COND include/linux/netfilter.h:278 [inline] ip_output+0x21d/0x8d0 net/ipv4/ip_output.c:405 dst_output include/net/dst.h:444 [inline] ip_local_out+0xc5/0x1b0 net/ipv4/ip_output.c:124 __ip_queue_xmit+0x9af/0x1f40 net/ipv4/ip_output.c:505 ip_queue_xmit+0x56/0x70 include/net/ip.h:198 __tcp_transmit_skb+0x1bb7/0x3bb0 net/ipv4/tcp_output.c:1160 tcp_transmit_skb net/ipv4/tcp_output.c:1176 [inline] tcp_send_syn_data net/ipv4/tcp_output.c:3498 [inline] tcp_connect+0x22d9/0x4690 net/ipv4/tcp_output.c:3537 tcp_v4_connect+0x19bb/0x1df0 net/ipv4/tcp_ipv4.c:315 __inet_stream_connect+0x992/0x1150 net/ipv4/af_inet.c:655 tcp_sendmsg_fastopen net/ipv4/tcp.c:1161 [inline] tcp_sendmsg_locked+0x2b0b/0x3f80 net/ipv4/tcp.c:1208 tcp_sendmsg+0x2f/0x50 net/ipv4/tcp.c:1443 inet_sendmsg+0x1a1/0x690 net/ipv4/af_inet.c:798 sock_sendmsg_nosec net/socket.c:621 [inline] sock_sendmsg+0xd5/0x120 net/socket.c:631 __sys_sendto+0x3d7/0x670 net/socket.c:1788 __do_sys_sendto net/socket.c:1800 [inline] __se_sys_sendto net/socket.c:1796 [inline] __x64_sys_sendto+0xe1/0x1a0 net/socket.c:1796 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x457659 Code: fd b3 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 cb b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f1192cb8c78 EFLAGS: 00000246 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 0000000000000006 RCX: 0000000000457659 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003 RBP: 000000000072bf00 R08: 00000000200008c0 R09: 0000000000000010 R10: 00000000200007fd R11: 0000000000000246 R12: 00007f1192cb96d4 R13: 00000000004c44f6 R14: 00000000004d7520 R15: 00000000ffffffff Allocated by task 11772: save_stack+0x43/0xd0 mm/kasan/kasan.c:448 set_track mm/kasan/kasan.c:460 [inline] kasan_kmalloc+0xc7/0xe0 mm/kasan/kasan.c:553 __do_kmalloc mm/slab.c:3722 [inline] __kmalloc+0x15b/0x760 mm/slab.c:3731 kmalloc include/linux/slab.h:551 [inline] kzalloc include/linux/slab.h:741 [inline] neigh_alloc net/core/neighbour.c:375 [inline] ___neigh_create+0x13fc/0x2600 net/core/neighbour.c:553 __neigh_create+0x30/0x40 net/core/neighbour.c:640 neigh_create include/net/neighbour.h:319 [inline] __neigh_lookup_errno include/net/neighbour.h:529 [inline] arp_req_set+0x59d/0xaa0 net/ipv4/arp.c:1066 arp_ioctl+0x48b/0xae0 net/ipv4/arp.c:1230 inet_ioctl+0x237/0x360 net/ipv4/af_inet.c:932 sock_do_ioctl+0xeb/0x420 net/socket.c:950 sock_ioctl+0x313/0x690 net/socket.c:1074 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:509 [inline] do_vfs_ioctl+0x1de/0x1790 fs/ioctl.c:696 ksys_ioctl+0xa9/0xd0 fs/ioctl.c:713 __do_sys_ioctl fs/ioctl.c:720 [inline] __se_sys_ioctl fs/ioctl.c:718 [inline] __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:718 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 6107: save_stack+0x43/0xd0 mm/kasan/kasan.c:448 set_track mm/kasan/kasan.c:460 [inline] __kasan_slab_free+0x102/0x150 mm/kasan/kasan.c:521 kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528 __cache_free mm/slab.c:3498 [inline] kfree+0xcf/0x230 mm/slab.c:3817 __rcu_reclaim kernel/rcu/rcu.h:233 [inline] rcu_do_batch kernel/rcu/tree.c:2437 [inline] invoke_rcu_callbacks kernel/rcu/tree.c:2716 [inline] rcu_process_callbacks+0x1140/0x1ac0 kernel/rcu/tree.c:2697 __do_softirq+0x308/0xb7e kernel/softirq.c:292 The buggy address belongs to the object at ffff8881997e6900 which belongs to the cache kmalloc-1k of size 1024 The buggy address is located 624 bytes inside of 1024-byte region [ffff8881997e6900, ffff8881997e6d00) The buggy address belongs to the page: page:ffffea000665f980 count:1 mapcount:0 mapping:ffff8881da800ac0 index:0xffff8881997e6000 compound_mapcount: 0 flags: 0x2fffc0000010200(slab|head) raw: 02fffc0000010200 ffffea0006652e08 ffffea000665f908 ffff8881da800ac0 raw: ffff8881997e6000 ffff8881997e6000 0000000100000006 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8881997e6a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8881997e6a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8881997e6b00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8881997e6b80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8881997e6c00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================