IPVS: ftp: loaded support on port[0] = 21
IPVS: ftp: loaded support on port[0] = 21
IPVS: ftp: loaded support on port[0] = 21
IPVS: ftp: loaded support on port[0] = 21
==================================================================
BUG: KASAN: use-after-free in __read_once_size include/linux/compiler.h:188 [inline]
BUG: KASAN: use-after-free in sk_dst_get include/net/sock.h:1772 [inline]
BUG: KASAN: use-after-free in pppol2tp_session_init net/l2tp/l2tp_ppp.c:587 [inline]
BUG: KASAN: use-after-free in pppol2tp_connect+0x1e60/0x1f60 net/l2tp/l2tp_ppp.c:747
Read of size 8 at addr ffff8801c13d5968 by task syz-executor1/8011

CPU: 1 PID: 8011 Comm: syz-executor1 Not tainted 4.16.0+ #1
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x1b9/0x29f lib/dump_stack.c:53
 print_address_description+0x6c/0x20b mm/kasan/report.c:256
 kasan_report_error mm/kasan/report.c:354 [inline]
 kasan_report.cold.7+0xac/0x2f5 mm/kasan/report.c:412
 __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:433
 __read_once_size include/linux/compiler.h:188 [inline]
 sk_dst_get include/net/sock.h:1772 [inline]
 pppol2tp_session_init net/l2tp/l2tp_ppp.c:587 [inline]
 pppol2tp_connect+0x1e60/0x1f60 net/l2tp/l2tp_ppp.c:747
 __sys_connect+0x37d/0x4c0 net/socket.c:1665
 SYSC_connect net/socket.c:1676 [inline]
 SyS_connect+0x24/0x30 net/socket.c:1673
 do_syscall_64+0x29e/0x9d0 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x455259
RSP: 002b:00007fc8562e7c68 EFLAGS: 00000246 ORIG_RAX: 000000000000002a
RAX: ffffffffffffffda RBX: 00007fc8562e86d4 RCX: 0000000000455259
RDX: 000000000000002e RSI: 00000000205fafd2 RDI: 0000000000000004
RBP: 000000000072bf58 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 000000000000005c R14: 00000000006f3940 R15: 0000000000000001

Allocated by task 8009:
 save_stack+0x43/0xd0 mm/kasan/kasan.c:447
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_kmalloc+0xc4/0xe0 mm/kasan/kasan.c:552
 kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:489
 kmem_cache_alloc+0x12e/0x760 mm/slab.c:3542
 sk_prot_alloc+0x69/0x2e0 net/core/sock.c:1468
 sk_alloc+0x104/0x17b0 net/core/sock.c:1528
 inet6_create+0x4f0/0x12a0 net/ipv6/af_inet6.c:183
 __sock_create+0x526/0x920 net/socket.c:1285
 sock_create net/socket.c:1325 [inline]
 __sys_socket+0x100/0x250 net/socket.c:1355
 SYSC_socket net/socket.c:1364 [inline]
 SyS_socket+0x24/0x30 net/socket.c:1362
 do_syscall_64+0x29e/0x9d0 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x42/0xb7

Freed by task 56:
 save_stack+0x43/0xd0 mm/kasan/kasan.c:447
 set_track mm/kasan/kasan.c:459 [inline]
 __kasan_slab_free+0x11a/0x170 mm/kasan/kasan.c:520
 kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:527
 __cache_free mm/slab.c:3486 [inline]
 kmem_cache_free+0x86/0x2d0 mm/slab.c:3744
 sk_prot_free net/core/sock.c:1509 [inline]
 __sk_destruct+0x6fe/0xa40 net/core/sock.c:1593
 sk_destruct+0x78/0x90 net/core/sock.c:1601
 __sk_free+0x22e/0x340 net/core/sock.c:1612
 sk_free+0x42/0x50 net/core/sock.c:1623
 sock_put include/net/sock.h:1664 [inline]
 l2tp_tunnel_free net/l2tp/l2tp_core.c:160 [inline]
 l2tp_tunnel_dec_refcount net/l2tp/l2tp_core.h:264 [inline]
 l2tp_tunnel_del_work+0x669/0x830 net/l2tp/l2tp_core.c:1307
 process_one_work+0xc1e/0x1b50 kernel/workqueue.c:2145
 worker_thread+0x1cc/0x1440 kernel/workqueue.c:2279
 kthread+0x345/0x410 kernel/kthread.c:238
 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:411

The buggy address belongs to the object at ffff8801c13d5740
 which belongs to the cache UDPv6 of size 1728
The buggy address is located 552 bytes inside of
 1728-byte region [ffff8801c13d5740, ffff8801c13d5e00)
The buggy address belongs to the page:
page:ffffea000704f540 count:1 mapcount:0 mapping:ffff8801c13d5000 index:0x0
flags: 0x2fffc0000000100(slab)
raw: 02fffc0000000100 ffff8801c13d5000 0000000000000000 0000000100000002
raw: ffffea0006c39120 ffffea0006b76ea0 ffff8801ce4da200 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801c13d5800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8801c13d5880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8801c13d5900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                          ^
 ffff8801c13d5980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8801c13d5a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================