do_dccp_getsockopt: sockopt(PACKET_SIZE) is deprecated: fix your app
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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 ffff8801cb62334b by task syz-executor6/25272

CPU: 0 PID: 25272 Comm: syz-executor6 Not tainted 4.15.0-rc9+ #206
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:00007f3d7176ec58 EFLAGS: 00000212 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 000000000071bea0 RCX: 0000000000452f19
RDX: 0000000000000000 RSI: 000000002000b000 RDI: 0000000000000013
RBP: 000000000000059c R08: 0000000020008000 R09: 000000000000001c
R10: 0000000000000000 R11: 0000000000000212 R12: 00000000006f7740
R13: 00000000ffffffff R14: 00007f3d7176f6d4 R15: 0000000000000000

Allocated by task 24947:
 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
 __do_kmalloc mm/slab.c:3708 [inline]
 __kmalloc+0x162/0x760 mm/slab.c:3717
 kmalloc include/linux/slab.h:504 [inline]
 sk_prot_alloc+0x101/0x2a0 net/core/sock.c:1471
 sk_alloc+0x105/0x1440 net/core/sock.c:1525
 alg_create+0x85/0x170 crypto/af_alg.c:375
 __sock_create+0x4d4/0x850 net/socket.c:1259
 sock_create net/socket.c:1299 [inline]
 SYSC_socket net/socket.c:1329 [inline]
 SyS_socket+0xeb/0x1d0 net/socket.c:1309
 entry_SYSCALL_64_fastpath+0x29/0xa0

Freed by task 24962:
 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]
 kfree+0xd6/0x260 mm/slab.c:3803
 sk_prot_free net/core/sock.c:1508 [inline]
 __sk_destruct+0x750/0x920 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]
 af_alg_release+0x5d/0x70 crypto/af_alg.c:126
 sock_release+0x8d/0x1e0 net/socket.c:595
 sock_close+0x16/0x20 net/socket.c:1123
 __fput+0x327/0x7e0 fs/file_table.c:210
 ____fput+0x15/0x20 fs/file_table.c:244
 task_work_run+0x199/0x270 kernel/task_work.c:113
 exit_task_work include/linux/task_work.h:22 [inline]
 do_exit+0x9bb/0x1ad0 kernel/exit.c:865
 do_group_exit+0x149/0x400 kernel/exit.c:968
 get_signal+0x73f/0x16c0 kernel/signal.c:2335
 do_signal+0x90/0x1eb0 arch/x86/kernel/signal.c:809
 exit_to_usermode_loop+0x214/0x310 arch/x86/entry/common.c:158
 prepare_exit_to_usermode arch/x86/entry/common.c:195 [inline]
 syscall_return_slowpath+0x490/0x550 arch/x86/entry/common.c:264
 entry_SYSCALL_64_fastpath+0x9e/0xa0

The buggy address belongs to the object at ffff8801cb623240
 which belongs to the cache kmalloc-2048 of size 2048
The buggy address is located 267 bytes inside of
 2048-byte region [ffff8801cb623240, ffff8801cb623a40)
The buggy address belongs to the page:
page:ffffea00072d8880 count:1 mapcount:0 mapping:ffff8801cb622140 index:0x0 compound_mapcount: 0
flags: 0x2fffc0000008100(slab|head)
raw: 02fffc0000008100 ffff8801cb622140 0000000000000000 0000000100000003
raw: ffffea0007545aa0 ffffea0007398620 ffff8801dac00c40 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801cb623200: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
 ffff8801cb623280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8801cb623300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                              ^
 ffff8801cb623380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8801cb623400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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