================================================================== BUG: KASAN: use-after-free in erspan_build_header+0x3bf/0x3d0 net/ipv4/ip_gre.c:698 Read of size 2 at addr ffff8801b2dc7acb by task syz-executor4/12197 CPU: 0 PID: 12197 Comm: syz-executor4 Not tainted 4.15.0+ #198 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: 0023:0xf7f88c79 RSP: 002b:00000000f778408c EFLAGS: 00000296 ORIG_RAX: 0000000000000171 RAX: ffffffffffffffda RBX: 0000000000000013 RCX: 0000000020e26000 RDX: 000000000000000e RSI: 0000000000000000 RDI: 0000000020dc9000 RBP: 0000000000000014 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 Allocated by task 12022: 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 getname_flags+0xcb/0x580 fs/namei.c:138 getname fs/namei.c:209 [inline] user_path_create fs/namei.c:3701 [inline] SYSC_mknodat fs/namei.c:3762 [inline] SyS_mknodat+0x17a/0x480 fs/namei.c:3750 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 Freed by task 12022: 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 putname+0xee/0x130 fs/namei.c:258 filename_create+0x245/0x520 fs/namei.c:3666 user_path_create fs/namei.c:3701 [inline] SYSC_mknodat fs/namei.c:3762 [inline] SyS_mknodat+0x18d/0x480 fs/namei.c:3750 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 The buggy address belongs to the object at ffff8801b2dc6e40 which belongs to the cache names_cache of size 4096 The buggy address is located 3211 bytes inside of 4096-byte region [ffff8801b2dc6e40, ffff8801b2dc7e40) The buggy address belongs to the page: page:ffffea0006cb7180 count:1 mapcount:0 mapping:ffff8801b2dc6e40 index:0x0 compound_mapcount: 0 flags: 0x2fffc0000008100(slab|head) raw: 02fffc0000008100 ffff8801b2dc6e40 0000000000000000 0000000100000001 raw: ffffea0006e56ca0 ffffea0006c2eda0 ffff8801da9d2600 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8801b2dc7980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8801b2dc7a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8801b2dc7a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8801b2dc7b00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8801b2dc7b80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================