==================================================================
BUG: KASAN: use-after-free in ext4_xattr_set_entry+0x1b8e/0x3b10 fs/ext4/xattr.c:1734
Read of size 4 at addr ffff88819ac5affe by task syz-fuzzer/1875

CPU: 0 PID: 1875 Comm: syz-fuzzer Not tainted 5.4.18-syzkaller-00145-g2d40d7b36ae9 #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+0x1b0/0x228 lib/dump_stack.c:118
 print_address_description+0x96/0x5d0 mm/kasan/report.c:374
 __kasan_report+0x14b/0x1c0 mm/kasan/report.c:506
 kasan_report+0x26/0x50 mm/kasan/common.c:634
 check_memory_region_inline mm/kasan/generic.c:182 [inline]
 check_memory_region+0x2c6/0x300 mm/kasan/generic.c:192
 memmove+0x28/0x60 mm/kasan/common.c:113
 ext4_xattr_set_entry+0x1b8e/0x3b10 fs/ext4/xattr.c:1734
 ext4_xattr_ibody_set fs/ext4/xattr.c:2236 [inline]
 ext4_xattr_set_handle+0xf46/0x2160 fs/ext4/xattr.c:2392
 ext4_initxattrs+0xa3/0x110 fs/ext4/xattr_security.c:43
 security_inode_init_security+0x25c/0x390 security/security.c:996
 ext4_init_security+0x34/0x40 fs/ext4/xattr_security.c:57
 __ext4_new_inode+0x4871/0x5e50 fs/ext4/ialloc.c:1155
 ext4_mkdir+0x41e/0x14c0 fs/ext4/namei.c:2763
 vfs_mkdir2+0x43b/0x610 fs/namei.c:3934
 do_mkdirat+0x1d7/0x300 fs/namei.c:3963
 __do_sys_mkdirat fs/namei.c:3974 [inline]
 __se_sys_mkdirat fs/namei.c:3972 [inline]
 __x64_sys_mkdirat+0x7b/0x90 fs/namei.c:3972
 do_syscall_64+0xc0/0x100 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x47c530
Code: 8b 7c 24 10 48 8b 74 24 18 48 8b 54 24 20 49 c7 c2 00 00 00 00 49 c7 c0 00 00 00 00 49 c7 c1 00 00 00 00 48 8b 44 24 08 0f 05 <48> 3d 01 f0 ff ff 76 20 48 c7 44 24 28 ff ff ff ff 48 c7 44 24 30
RSP: 002b:000000c437419778 EFLAGS: 00000212 ORIG_RAX: 0000000000000102
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000047c530
RDX: 00000000000001c0 RSI: 000000c425a08240 RDI: ffffffffffffff9c
RBP: 000000c4374197d8 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000212 R12: ffffffffffffffff
R13: 0000000000000013 R14: 0000000000000012 R15: 0000000000000100

The buggy address belongs to the page:
page:ffffea00066b1680 refcount:2 mapcount:0 mapping:ffff8881d97dc5f8 index:0x42f
def_blk_aops
flags: 0x800000000000203a(referenced|dirty|lru|active|private)
raw: 800000000000203a ffffea00066b1008 ffffea0006b3f788 ffff8881d97dc5f8
raw: 000000000000042f ffff8881d6a81b28 00000002ffffffff ffff8881da944000
page dumped because: kasan: bad access detected
page->mem_cgroup:ffff8881da944000

Memory state around the buggy address:
 ffff88819ac5af00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88819ac5af80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff88819ac5b000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                   ^
 ffff88819ac5b080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88819ac5b100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================