overlayfs: missing 'lowerdir'
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BUG: KASAN: slab-out-of-bounds in memcpy include/linux/string.h:347 [inline]
BUG: KASAN: slab-out-of-bounds in pdu_read+0x90/0xd0 net/9p/protocol.c:64
Read of size 33767 at addr ffff8882097a8cad by task syz-executor.4/32176

CPU: 1 PID: 32176 Comm: syz-executor.4 Not tainted 4.14.157-syzkaller #0
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+0x142/0x197 lib/dump_stack.c:58
 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+0xa9/0x2af mm/kasan/report.c:393
 check_memory_region_inline mm/kasan/kasan.c:260 [inline]
 check_memory_region+0x123/0x190 mm/kasan/kasan.c:267
 memcpy+0x24/0x50 mm/kasan/kasan.c:302
 memcpy include/linux/string.h:347 [inline]
 pdu_read+0x90/0xd0 net/9p/protocol.c:64
 p9pdu_vreadf net/9p/protocol.c:167 [inline]
 p9pdu_readf+0x379/0x1780 net/9p/protocol.c:540
IPv6: ADDRCONF(NETDEV_CHANGE): lo: link becomes ready
IPv6: ADDRCONF(NETDEV_CHANGE): lo: link becomes ready
 p9_client_version net/9p/client.c:990 [inline]
 p9_client_create+0xa1f/0x1120 net/9p/client.c:1088
IPv6: ADDRCONF(NETDEV_CHANGE): lo: link becomes ready
 v9fs_session_init+0x1dc/0x1620 fs/9p/v9fs.c:422
 v9fs_mount+0x7d/0x870 fs/9p/vfs_super.c:135
 mount_fs+0x97/0x2a1 fs/super.c:1237
 vfs_kern_mount.part.0+0x5e/0x3d0 fs/namespace.c:1046
 vfs_kern_mount fs/namespace.c:1036 [inline]
 do_new_mount fs/namespace.c:2549 [inline]
 do_mount+0x417/0x27d0 fs/namespace.c:2879
 SYSC_mount fs/namespace.c:3095 [inline]
 SyS_mount+0xab/0x120 fs/namespace.c:3072
 do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x45a679
RSP: 002b:00007f54ee6c5c78 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 0000000000000005 RCX: 000000000045a679
RDX: 0000000020000040 RSI: 0000000020000000 RDI: 0000000000000000
RBP: 000000000075bf20 R08: 0000000020000080 R09: 0000000000000000
R10: 0000000000200004 R11: 0000000000000246 R12: 00007f54ee6c66d4
R13: 00000000004c7981 R14: 00000000004de788 R15: 00000000ffffffff

Allocated by task 32176:
 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
 __do_kmalloc mm/slab.c:3720 [inline]
 __kmalloc+0x15d/0x7a0 mm/slab.c:3729
 kmalloc include/linux/slab.h:493 [inline]
 p9_fcall_alloc+0x1d/0x90 net/9p/client.c:242
 p9_tag_alloc net/9p/client.c:312 [inline]
 p9_client_prepare_req.part.0+0x73a/0xa90 net/9p/client.c:728
 p9_client_prepare_req net/9p/client.c:718 [inline]
 p9_client_rpc+0x170/0x1180 net/9p/client.c:763
 p9_client_version net/9p/client.c:980 [inline]
 p9_client_create+0x997/0x1120 net/9p/client.c:1088
 v9fs_session_init+0x1dc/0x1620 fs/9p/v9fs.c:422
 v9fs_mount+0x7d/0x870 fs/9p/vfs_super.c:135
 mount_fs+0x97/0x2a1 fs/super.c:1237
 vfs_kern_mount.part.0+0x5e/0x3d0 fs/namespace.c:1046
 vfs_kern_mount fs/namespace.c:1036 [inline]
 do_new_mount fs/namespace.c:2549 [inline]
 do_mount+0x417/0x27d0 fs/namespace.c:2879
 SYSC_mount fs/namespace.c:3095 [inline]
 SyS_mount+0xab/0x120 fs/namespace.c:3072
 do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7

Freed by task 28719:
 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]
 kfree+0xcc/0x270 mm/slab.c:3815
 __sock_kfree_s net/core/sock.c:2000 [inline]
 sock_kfree_s+0x29/0x50 net/core/sock.c:2006
 ___sys_sendmsg+0x436/0x840 net/socket.c:2076
 __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+0x1e8/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7

The buggy address belongs to the object at ffff8882097a8c80
 which belongs to the cache kmalloc-16384 of size 16384
The buggy address is located 45 bytes inside of
 16384-byte region [ffff8882097a8c80, ffff8882097acc80)
The buggy address belongs to the page:
page:ffffea000825ea00 count:1 mapcount:0 mapping:ffff8882097a8c80 index:0x0 compound_mapcount: 0
flags: 0x57ffe0000008100(slab|head)
raw: 057ffe0000008100 ffff8882097a8c80 0000000000000000 0000000100000001
raw: ffffea00082e2c20 ffff88821f800c48 ffff8880aa802200 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8882097aab80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8882097aac00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff8882097aac80: 00 00 00 00 fc fc fc fc fc fc fc fc fc fc fc fc
                               ^
 ffff8882097aad00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8882097aad80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
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