================================================================== BUG: KASAN: use-after-free in __list_add_valid+0x8f/0xac lib/list_debug.c:26 Read of size 8 at addr ffff8881b945d4b0 by task syz-executor1/7672 CPU: 0 PID: 7672 Comm: syz-executor1 Not tainted 4.20.0-rc6-next-20181210+ #164 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.4+0x9/0x1ff mm/kasan/report.c:187 kasan_report.cold.5+0x1b/0x39 mm/kasan/report.c:317 __asan_report_load8_noabort+0x14/0x20 mm/kasan/generic_report.c:135 __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 sctp_v4_xmit+0x1a7/0x200 net/sctp/protocol.c:991 sctp_packet_transmit+0x1f1d/0x3d00 net/sctp/output.c:641 sctp_packet_singleton net/sctp/outqueue.c:787 [inline] sctp_outq_flush_ctrl.constprop.11+0x7a9/0xe50 net/sctp/outqueue.c:918 sctp_outq_flush+0x310/0x34f0 net/sctp/outqueue.c:1200 sctp_outq_uncork+0x6a/0x80 net/sctp/outqueue.c:772 sctp_cmd_interpreter net/sctp/sm_sideeffect.c:1820 [inline] sctp_side_effects net/sctp/sm_sideeffect.c:1220 [inline] sctp_do_sm+0x5ff/0x7190 net/sctp/sm_sideeffect.c:1191 sctp_primitive_ASSOCIATE+0x9d/0xd0 net/sctp/primitive.c:88 __sctp_connect+0x9aa/0xda0 net/sctp/socket.c:1226 __sctp_setsockopt_connectx+0x134/0x190 net/sctp/socket.c:1349 sctp_setsockopt_connectx_old net/sctp/socket.c:1365 [inline] sctp_setsockopt+0x2109/0x7380 net/sctp/socket.c:4380 sock_common_setsockopt+0x9a/0xe0 net/core/sock.c:2986 __sys_setsockopt+0x1ba/0x3c0 net/socket.c:1903 __do_sys_setsockopt net/socket.c:1914 [inline] __se_sys_setsockopt net/socket.c:1911 [inline] __x64_sys_setsockopt+0xbe/0x150 net/socket.c:1911 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:00007f04322bdc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000036 RAX: ffffffffffffffda RBX: 0000000000000005 RCX: 0000000000457659 RDX: 000000000000006b RSI: 0000000000000084 RDI: 0000000000000006 RBP: 000000000072bfa0 R08: 0000000000000010 R09: 0000000000000000 R10: 0000000020000000 R11: 0000000000000246 R12: 00007f04322be6d4 R13: 00000000004cb718 R14: 00000000004d8678 R15: 00000000ffffffff Allocated by task 7660: save_stack+0x43/0xd0 mm/kasan/common.c:73 set_track mm/kasan/common.c:85 [inline] kasan_kmalloc+0xcb/0xd0 mm/kasan/common.c:482 __do_kmalloc mm/slab.c:3709 [inline] __kmalloc+0x15d/0x760 mm/slab.c:3718 kmalloc include/linux/slab.h:550 [inline] kzalloc include/linux/slab.h:740 [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:951 sock_ioctl+0x313/0x690 net/socket.c:1075 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 9: save_stack+0x43/0xd0 mm/kasan/common.c:73 set_track mm/kasan/common.c:85 [inline] __kasan_slab_free+0x102/0x150 mm/kasan/common.c:444 kasan_slab_free+0xe/0x10 mm/kasan/common.c:452 __cache_free mm/slab.c:3485 [inline] kfree+0xcf/0x230 mm/slab.c:3804 __rcu_reclaim kernel/rcu/rcu.h:233 [inline] rcu_do_batch kernel/rcu/tree.c:2452 [inline] invoke_rcu_callbacks kernel/rcu/tree.c:2773 [inline] rcu_process_callbacks+0xd91/0x15f0 kernel/rcu/tree.c:2754 __do_softirq+0x308/0xb7e kernel/softirq.c:292 The buggy address belongs to the object at ffff8881b945d240 which belongs to the cache kmalloc-1k of size 1024 The buggy address is located 624 bytes inside of 1024-byte region [ffff8881b945d240, ffff8881b945d640) The buggy address belongs to the page: page:ffffea0006e51700 count:1 mapcount:0 mapping:ffff8881da800ac0 index:0xffff8881b945c040 compound_mapcount: 0 flags: 0x2fffc0000010200(slab|head) raw: 02fffc0000010200 ffffea0007097208 ffffea0006e3f988 ffff8881da800ac0 raw: ffff8881b945c040 ffff8881b945c040 0000000100000006 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8881b945d380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8881b945d400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8881b945d480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8881b945d500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8881b945d580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================