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BUG: KASAN: use-after-free in erspan_xmit+0x22d4/0x2430 net/ipv4/ip_gre.c:735
Read of size 2 at addr ffff8801cc75284b by task syz-executor2/4255

CPU: 0 PID: 4255 Comm: syz-executor2 Not tainted 4.15.0-rc8+ #204
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+0x194/0x257 lib/dump_stack.c:53
 print_address_description+0x73/0x250 mm/kasan/report.c:252
 kasan_report_error mm/kasan/report.c:351 [inline]
 kasan_report+0x25b/0x340 mm/kasan/report.c:409
 __asan_report_load_n_noabort+0xf/0x20 mm/kasan/report.c:440
 erspan_xmit+0x22d4/0x2430 net/ipv4/ip_gre.c:735
 __netdev_start_xmit include/linux/netdevice.h:4055 [inline]
 netdev_start_xmit include/linux/netdevice.h:4064 [inline]
 packet_direct_xmit+0x3ad/0x790 net/packet/af_packet.c:267
 packet_snd net/packet/af_packet.c:2944 [inline]
 packet_sendmsg+0x3aed/0x60b0 net/packet/af_packet.c:2969
 sock_sendmsg_nosec net/socket.c:630 [inline]
 sock_sendmsg+0xca/0x110 net/socket.c:640
 SYSC_sendto+0x361/0x5c0 net/socket.c:1721
 SyS_sendto+0x40/0x50 net/socket.c:1689
 entry_SYSCALL_64_fastpath+0x29/0xa0
RIP: 0033:0x452f19
RSP: 002b:00007fbfbf664c58 EFLAGS: 00000212 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 000000000071bea0 RCX: 0000000000452f19
RDX: 0000000000000000 RSI: 0000000020003fd9 RDI: 0000000000000013
RBP: 000000000000059c R08: 0000000020008000 R09: 000000000000001c
R10: 0000000000000000 R11: 0000000000000212 R12: 00000000006f7740
R13: 00000000ffffffff R14: 00007fbfbf6656d4 R15: 0000000000000000

Allocated by task 2990:
 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:551
 kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:489
 kmem_cache_alloc+0x12e/0x760 mm/slab.c:3544
 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:1259
 sock_create net/socket.c:1299 [inline]
 SYSC_socketpair net/socket.c:1383 [inline]
 SyS_socketpair+0x1c0/0x6f0 net/socket.c:1340
 entry_SYSCALL_64_fastpath+0x29/0xa0

Freed by task 2990:
 save_stack+0x43/0xd0 mm/kasan/kasan.c:447
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_slab_free+0x71/0xc0 mm/kasan/kasan.c:524
 __cache_free mm/slab.c:3488 [inline]
 kmem_cache_free+0x83/0x2a0 mm/slab.c:3746
 sk_prot_free net/core/sock.c:1506 [inline]
 __sk_destruct+0x628/0x920 net/core/sock.c:1590
 sk_destruct+0x47/0x80 net/core/sock.c:1598
 __sk_free+0xf1/0x2b0 net/core/sock.c:1609
 sk_free+0x2a/0x40 net/core/sock.c:1620
 sock_put include/net/sock.h:1658 [inline]
 sk_common_release+0x1f0/0x2f0 net/core/sock.c:3029
 raw_close+0x2b/0x30 net/ipv4/raw.c:705
 inet_release+0xed/0x1c0 net/ipv4/af_inet.c:427
 sock_release+0x8d/0x1e0 net/socket.c:595
 SYSC_socketpair net/socket.c:1396 [inline]
 SyS_socketpair+0x4b4/0x6f0 net/socket.c:1340
 entry_SYSCALL_64_fastpath+0x29/0xa0

The buggy address belongs to the object at ffff8801cc752840
 which belongs to the cache RAW of size 1296
The buggy address is located 11 bytes inside of
 1296-byte region [ffff8801cc752840, ffff8801cc752d50)
The buggy address belongs to the page:
page:ffffea000731d480 count:1 mapcount:0 mapping:ffff8801cc752280 index:0xffff8801cc752280 compound_mapcount: 0
flags: 0x2fffc0000008100(slab|head)
raw: 02fffc0000008100 ffff8801cc752280 ffff8801cc752280 0000000100000003
raw: ffff8801d6f60c38 ffffea0006bb7620 ffff8801d6f5f7c0 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801cc752700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8801cc752780: fb fb fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff8801cc752800: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
                                              ^
 ffff8801cc752880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8801cc752900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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