audit: type=1400 audit(1520316131.253:8): avc:  denied  { map } for  pid=4120 comm="syz-execprog" path="/root/syzkaller-shm702001817" dev="sda1" ino=16482 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:object_r:file_t:s0 tclass=file permissive=1
IPVS: ftp: loaded support on port[0] = 21
==================================================================
BUG: KASAN: slab-out-of-bounds in setup_udp_tunnel_sock+0x3ee/0x5f0 net/ipv4/udp_tunnel.c:69
Write of size 1 at addr ffff8801c93d2b50 by task syz-executor0/4129

CPU: 0 PID: 4129 Comm: syz-executor0 Not tainted 4.16.0-rc4+ #252
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+0x194/0x24d lib/dump_stack.c:53
 print_address_description+0x73/0x250 mm/kasan/report.c:256
 kasan_report_error mm/kasan/report.c:354 [inline]
 kasan_report+0x23c/0x360 mm/kasan/report.c:412
 __asan_report_store1_noabort+0x17/0x20 mm/kasan/report.c:435
 setup_udp_tunnel_sock+0x3ee/0x5f0 net/ipv4/udp_tunnel.c:69
 l2tp_tunnel_create+0x1361/0x1800 net/l2tp/l2tp_core.c:1538
 pppol2tp_connect+0x14b8/0x1dd0 net/l2tp/l2tp_ppp.c:698
 SYSC_connect+0x213/0x4a0 net/socket.c:1639
 SyS_connect+0x24/0x30 net/socket.c:1620
 do_syscall_32_irqs_on arch/x86/entry/common.c:330 [inline]
 do_fast_syscall_32+0x3ec/0xf9f arch/x86/entry/common.c:392
 entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139
RIP: 0023:0xf7fc5c99
RSP: 002b:00000000ffa2fadc EFLAGS: 00000282 ORIG_RAX: 000000000000016a
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00000000200000c0
RDX: 000000000000002e RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000

Allocated by task 4129:
 save_stack+0x43/0xd0 mm/kasan/kasan.c:447
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_kmalloc+0xad/0xe0 mm/kasan/kasan.c:552
 kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:489
 kmem_cache_alloc+0x12e/0x760 mm/slab.c:3541
 sk_prot_alloc+0x65/0x2a0 net/core/sock.c:1465
 sk_alloc+0x105/0x1440 net/core/sock.c:1525
 inet_create+0x47c/0xf50 net/ipv4/af_inet.c:320
 __sock_create+0x4d4/0x850 net/socket.c:1285
 sock_create net/socket.c:1325 [inline]
 SYSC_socket net/socket.c:1355 [inline]
 SyS_socket+0xeb/0x1d0 net/socket.c:1335
 do_syscall_32_irqs_on arch/x86/entry/common.c:330 [inline]
 do_fast_syscall_32+0x3ec/0xf9f arch/x86/entry/common.c:392
 entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139

Freed by task 0:
(stack is not available)

The buggy address belongs to the object at ffff8801c93d2640
 which belongs to the cache RAW of size 1296
The buggy address is located 0 bytes to the right of
 1296-byte region [ffff8801c93d2640, ffff8801c93d2b50)
The buggy address belongs to the page:
page:ffffea000724f480 count:1 mapcount:0 mapping:ffff8801c93d2080 index:0x0 compound_mapcount: 0
flags: 0x2fffc0000008100(slab|head)
raw: 02fffc0000008100 ffff8801c93d2080 0000000000000000 0000000100000005
raw: ffffea0007544fa0 ffff8801d5401e48 ffff8801d5402e00 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801c93d2a00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8801c93d2a80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff8801c93d2b00: 00 00 00 00 00 00 00 00 00 00 fc fc fc fc fc fc
                                                 ^
 ffff8801c93d2b80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8801c93d2c00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
==================================================================