================================================================== BUG: KASAN: use-after-free in erspan_build_header+0x3bf/0x3d0 net/ipv4/ip_gre.c:698 Read of size 2 at addr ffff8801d82c02cb by task syzkaller122068/3656 CPU: 0 PID: 3656 Comm: syzkaller122068 Not tainted 4.15.0-rc9+ #184 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_build_header+0x3bf/0x3d0 net/ipv4/ip_gre.c:698 erspan_xmit+0x3b8/0x13b0 net/ipv4/ip_gre.c:740 __netdev_start_xmit include/linux/netdevice.h:4042 [inline] netdev_start_xmit include/linux/netdevice.h:4051 [inline] packet_direct_xmit+0x315/0x6b0 net/packet/af_packet.c:266 packet_snd net/packet/af_packet.c:2943 [inline] packet_sendmsg+0x3aed/0x60b0 net/packet/af_packet.c:2968 sock_sendmsg_nosec net/socket.c:638 [inline] sock_sendmsg+0xca/0x110 net/socket.c:648 SYSC_sendto+0x361/0x5c0 net/socket.c:1729 SyS_sendto+0x40/0x50 net/socket.c:1697 do_syscall_32_irqs_on arch/x86/entry/common.c:327 [inline] do_fast_syscall_32+0x3ee/0xf9d arch/x86/entry/common.c:389 entry_SYSENTER_compat+0x54/0x63 arch/x86/entry/entry_64_compat.S:129 RIP: 0023:0xf7f6fc79 RSP: 002b:00000000ffc3bb3c EFLAGS: 00000282 ORIG_RAX: 0000000000000171 RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 0000000020003fd9 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000020008000 RBP: 000000000000001c R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 The buggy address belongs to the page: page:ffffea000760b000 count:0 mapcount:-127 mapping: (null) index:0xffff8801d82c08c0 flags: 0x2fffc0000000000() raw: 02fffc0000000000 0000000000000000 ffff8801d82c08c0 00000000ffffff80 raw: ffffea0007601020 ffffea000760ae20 0000000000000001 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8801d82c0180: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff8801d82c0200: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff >ffff8801d82c0280: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ^ ffff8801d82c0300: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff8801d82c0380: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ==================================================================