overlayfs: missing 'lowerdir'
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BUG: KASAN: use-after-free in memmove include/linux/string.h:392 [inline]
BUG: KASAN: use-after-free in ext4_xattr_set_entry+0xbc7/0x3690 fs/ext4/xattr.c:1738
Read of size 4 at addr ffff88804d113ffe by task syz-executor.2/2288
overlayfs: overlapping lowerdir path

CPU: 1 PID: 2288 Comm: syz-executor.2 Not tainted 4.19.176-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1fc/0x2ef lib/dump_stack.c:118
 print_address_description.cold+0x54/0x219 mm/kasan/report.c:256
 kasan_report_error.cold+0x8a/0x1b9 mm/kasan/report.c:354
 kasan_report+0x8f/0xa0 mm/kasan/report.c:412
 memmove+0x20/0x50 mm/kasan/kasan.c:293
 memmove include/linux/string.h:392 [inline]
 ext4_xattr_set_entry+0xbc7/0x3690 fs/ext4/xattr.c:1738
overlayfs: upper fs does not support xattr, falling back to index=off and metacopy=off.
 ext4_xattr_ibody_set+0x81/0x2a0 fs/ext4/xattr.c:2243
 ext4_xattr_set_handle+0x5ad/0xfa0 fs/ext4/xattr.c:2399
 ext4_xattr_set+0x135/0x2a0 fs/ext4/xattr.c:2511
 __vfs_setxattr+0x10e/0x170 fs/xattr.c:149
 __vfs_setxattr_noperm+0x11a/0x420 fs/xattr.c:180
 __vfs_setxattr_locked+0x176/0x250 fs/xattr.c:238
 vfs_setxattr+0xe5/0x270 fs/xattr.c:255
 setxattr+0x23d/0x330 fs/xattr.c:520
 path_setxattr+0x170/0x190 fs/xattr.c:539
 __do_sys_setxattr fs/xattr.c:554 [inline]
 __se_sys_setxattr fs/xattr.c:550 [inline]
 __x64_sys_setxattr+0xc0/0x160 fs/xattr.c:550
 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x465ef9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f27c2559188 EFLAGS: 00000246 ORIG_RAX: 00000000000000bc
RAX: ffffffffffffffda RBX: 000000000056bf60 RCX: 0000000000465ef9
RDX: 00000000200001c0 RSI: 0000000020000080 RDI: 0000000020000040
RBP: 00000000004bcd1c R08: 0700000000000000 R09: 0000000000000000
R10: 0000000000000078 R11: 0000000000000246 R12: 000000000056bf60
R13: 00007ffe72f3409f R14: 00007f27c2559300 R15: 0000000000022000

The buggy address belongs to the page:
page:ffffea00013444c0 count:2 mapcount:0 mapping:ffff888239b16b60 index:0x408
flags: 0xfff00000001074(referenced|dirty|lru|active|private)
raw: 00fff00000001074 ffffea000128de88 ffffea000128e188 ffff888239b16b60
raw: 0000000000000408 ffff88804d90e930 00000002ffffffff ffff88823b2d08c0
page dumped because: kasan: bad access detected
page->mem_cgroup:ffff88823b2d08c0

Memory state around the buggy address:
 ffff88804d113f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88804d113f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff88804d114000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                   ^
 ffff88804d114080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88804d114100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
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