==================================================================
BUG: KASAN: use-after-free in erspan_build_header+0x392/0x3b0 net/ipv4/ip_gre.c:706
Read of size 2 at addr ffff888084d1f58b by task syz-executor.3/7335

CPU: 0 PID: 7335 Comm: syz-executor.3 Not tainted 4.14.119 #11
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+0x138/0x19c lib/dump_stack.c:53
 print_address_description.cold+0x7c/0x1dc mm/kasan/report.c:252
 kasan_report_error mm/kasan/report.c:351 [inline]
 kasan_report mm/kasan/report.c:409 [inline]
 kasan_report.cold+0x11e/0x2db mm/kasan/report.c:393
 __asan_report_load_n_noabort+0xf/0x20 mm/kasan/report.c:440
 erspan_build_header+0x392/0x3b0 net/ipv4/ip_gre.c:706
 erspan_xmit net/ipv4/ip_gre.c:748 [inline]
 erspan_xmit+0x3ec/0x11c0 net/ipv4/ip_gre.c:725
 __netdev_start_xmit include/linux/netdevice.h:4033 [inline]
 netdev_start_xmit include/linux/netdevice.h:4042 [inline]
 packet_direct_xmit+0x438/0x640 net/packet/af_packet.c:269
 packet_snd net/packet/af_packet.c:2973 [inline]
 packet_sendmsg+0x329f/0x5930 net/packet/af_packet.c:2998
 sock_sendmsg_nosec net/socket.c:646 [inline]
 sock_sendmsg+0xd0/0x110 net/socket.c:656
 ___sys_sendmsg+0x70c/0x850 net/socket.c:2062
 __sys_sendmsg+0xb9/0x140 net/socket.c:2096
 SYSC_sendmsg net/socket.c:2107 [inline]
 SyS_sendmsg+0x2d/0x50 net/socket.c:2103
 do_syscall_64+0x1eb/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x458da9
RSP: 002b:00007f94dfb7ac78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000458da9
RDX: 0000000000000000 RSI: 00000000200000c0 RDI: 0000000000000003
RBP: 000000000073bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f94dfb7b6d4
R13: 00000000004c6745 R14: 00000000004db370 R15: 00000000ffffffff

Allocated by task 0:
 save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:59
 save_stack+0x45/0xd0 mm/kasan/kasan.c:447
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_kmalloc mm/kasan/kasan.c:551 [inline]
 kasan_kmalloc+0xce/0xf0 mm/kasan/kasan.c:529
 kasan_slab_alloc+0xf/0x20 mm/kasan/kasan.c:489
 kmem_cache_alloc+0x12e/0x780 mm/slab.c:3552
 skb_clone+0x129/0x310 net/core/skbuff.c:1282
 skb_share_check include/linux/skbuff.h:1538 [inline]
 packet_rcv_spkt+0x424/0x560 net/packet/af_packet.c:1857
 deliver_skb net/core/dev.c:1881 [inline]
 deliver_ptype_list_skb net/core/dev.c:1896 [inline]
 __netif_receive_skb_core+0x9be/0x2ae0 net/core/dev.c:4460
 __netif_receive_skb+0x2c/0x1b0 net/core/dev.c:4515
 netif_receive_skb_internal+0xe4/0x5a0 net/core/dev.c:4588
 napi_skb_finish net/core/dev.c:4949 [inline]
 napi_gro_receive+0x2fb/0x410 net/core/dev.c:4980
 receive_buf+0x532/0x3fd0 drivers/net/virtio_net.c:852
 virtnet_receive drivers/net/virtio_net.c:1098 [inline]
 virtnet_poll+0x515/0xa6e drivers/net/virtio_net.c:1189
 napi_poll net/core/dev.c:5595 [inline]
 net_rx_action+0x495/0xf80 net/core/dev.c:5661
 __do_softirq+0x24e/0x9ae kernel/softirq.c:288

Freed by task 0:
 save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:59
 save_stack+0x45/0xd0 mm/kasan/kasan.c:447
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_slab_free+0x75/0xc0 mm/kasan/kasan.c:524
 __cache_free mm/slab.c:3496 [inline]
 kmem_cache_free+0x83/0x2b0 mm/slab.c:3758
 kfree_skbmem net/core/skbuff.c:586 [inline]
 kfree_skbmem+0xac/0x120 net/core/skbuff.c:580
 __kfree_skb net/core/skbuff.c:646 [inline]
 kfree_skb+0xbd/0x350 net/core/skbuff.c:663
 packet_rcv_spkt+0xd9/0x560 net/packet/af_packet.c:1888
 deliver_skb net/core/dev.c:1881 [inline]
 deliver_ptype_list_skb net/core/dev.c:1896 [inline]
 __netif_receive_skb_core+0x9be/0x2ae0 net/core/dev.c:4460
 __netif_receive_skb+0x2c/0x1b0 net/core/dev.c:4515
 netif_receive_skb_internal+0xe4/0x5a0 net/core/dev.c:4588
 napi_skb_finish net/core/dev.c:4949 [inline]
 napi_gro_receive+0x2fb/0x410 net/core/dev.c:4980
 receive_buf+0x532/0x3fd0 drivers/net/virtio_net.c:852
 virtnet_receive drivers/net/virtio_net.c:1098 [inline]
 virtnet_poll+0x515/0xa6e drivers/net/virtio_net.c:1189
 napi_poll net/core/dev.c:5595 [inline]
 net_rx_action+0x495/0xf80 net/core/dev.c:5661
 __do_softirq+0x24e/0x9ae kernel/softirq.c:288

The buggy address belongs to the object at ffff888084d1f500
 which belongs to the cache skbuff_head_cache of size 232
The buggy address is located 139 bytes inside of
 232-byte region [ffff888084d1f500, ffff888084d1f5e8)
The buggy address belongs to the page:
page:ffffea00021347c0 count:1 mapcount:0 mapping:ffff888084d1f000 index:0x0
flags: 0x1fffc0000000100(slab)
raw: 01fffc0000000100 ffff888084d1f000 0000000000000000 000000010000000c
raw: ffffea000294dee0 ffffea00020e5260 ffff88821b757240 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff888084d1f480: fb fb fb fb fb fc fc fc fc fc fc fc fc fc fc fc
 ffff888084d1f500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888084d1f580: fb fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc
                      ^
 ffff888084d1f600: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
 ffff888084d1f680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================