================================================================== BUG: KASAN: use-after-free in __list_add_valid+0x8f/0xac lib/list_debug.c:26 Read of size 8 at addr ffff8881bbfc74b0 by task syz-executor2/11097 CPU: 1 PID: 11097 Comm: syz-executor2 Not tainted 4.20.0-rc4+ #335 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+0xb8b/0x1860 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:3479 [inline] tcp_connect+0x22d9/0x4690 net/ipv4/tcp_output.c:3518 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:00007f447dac6c78 EFLAGS: 00000246 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 0000000000000006 RCX: 0000000000457659 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003 RBP: 000000000072bf00 R08: 0000000020e68000 R09: 0000000000000010 R10: 00000000200007fd R11: 0000000000000246 R12: 00007f447dac76d4 R13: 00000000004c44f6 R14: 00000000004d7520 R15: 00000000ffffffff Allocated by task 5979: 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 kmem_cache_alloc_trace+0x152/0x750 mm/slab.c:3620 kmalloc include/linux/slab.h:546 [inline] syslog_print kernel/printk/printk.c:1301 [inline] do_syslog+0xb9b/0x1690 kernel/printk/printk.c:1469 kmsg_read+0x8f/0xc0 fs/proc/kmsg.c:40 proc_reg_read+0x2a3/0x3d0 fs/proc/inode.c:231 __vfs_read+0x117/0x9b0 fs/read_write.c:416 vfs_read+0x17f/0x3c0 fs/read_write.c:452 ksys_read+0x101/0x260 fs/read_write.c:578 __do_sys_read fs/read_write.c:588 [inline] __se_sys_read fs/read_write.c:586 [inline] __x64_sys_read+0x73/0xb0 fs/read_write.c:586 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 5979: 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 syslog_print kernel/printk/printk.c:1352 [inline] do_syslog+0x147b/0x1690 kernel/printk/printk.c:1469 kmsg_read+0x8f/0xc0 fs/proc/kmsg.c:40 proc_reg_read+0x2a3/0x3d0 fs/proc/inode.c:231 __vfs_read+0x117/0x9b0 fs/read_write.c:416 vfs_read+0x17f/0x3c0 fs/read_write.c:452 ksys_read+0x101/0x260 fs/read_write.c:578 __do_sys_read fs/read_write.c:588 [inline] __se_sys_read fs/read_write.c:586 [inline] __x64_sys_read+0x73/0xb0 fs/read_write.c:586 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe The buggy address belongs to the object at ffff8881bbfc7240 which belongs to the cache kmalloc-1k of size 1024 The buggy address is located 624 bytes inside of 1024-byte region [ffff8881bbfc7240, ffff8881bbfc7640) The buggy address belongs to the page: page:ffffea0006eff180 count:1 mapcount:0 mapping:ffff8881da800ac0 index:0xffff8881bbfc7b40 compound_mapcount: 0 flags: 0x2fffc0000010200(slab|head) raw: 02fffc0000010200 ffffea0006ec0a08 ffffea0007029288 ffff8881da800ac0 raw: ffff8881bbfc7b40 ffff8881bbfc6040 0000000100000006 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8881bbfc7380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8881bbfc7400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8881bbfc7480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8881bbfc7500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8881bbfc7580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================