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BUG: KASAN: use-after-free in ext4_xattr_set_entry+0x35de/0x3770 fs/ext4/xattr.c:1600
Read of size 4 at addr ffff88807af19084 by task syz-executor.4/11002

CPU: 1 PID: 11002 Comm: syz-executor.4 Not tainted 5.3.0-rc6+ #128
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+0x172/0x1f0 lib/dump_stack.c:113
 print_address_description.cold+0xd4/0x306 mm/kasan/report.c:351
 __kasan_report.cold+0x1b/0x36 mm/kasan/report.c:482
 kasan_report+0x12/0x17 mm/kasan/common.c:618
 __asan_report_load4_noabort+0x14/0x20 mm/kasan/generic_report.c:131
 ext4_xattr_set_entry+0x35de/0x3770 fs/ext4/xattr.c:1600
 ext4_xattr_ibody_set+0x80/0x2d0 fs/ext4/xattr.c:2236
 ext4_xattr_set_handle+0x821/0x1090 fs/ext4/xattr.c:2392
 ext4_xattr_set+0x1e5/0x370 fs/ext4/xattr.c:2504
 ext4_xattr_trusted_set+0x36/0x40 fs/ext4/xattr_trusted.c:37
 __vfs_setxattr+0x11f/0x180 fs/xattr.c:150
 __vfs_setxattr_noperm+0x11c/0x410 fs/xattr.c:181
 vfs_setxattr+0xda/0x100 fs/xattr.c:224
 ovl_do_setxattr fs/overlayfs/overlayfs.h:151 [inline]
 ovl_make_workdir fs/overlayfs/super.c:1106 [inline]
 ovl_get_workdir fs/overlayfs/super.c:1170 [inline]
 ovl_fill_super+0x1288/0x406e fs/overlayfs/super.c:1590
 mount_nodev+0x66/0x110 fs/super.c:1329
 ovl_mount+0x2d/0x40 fs/overlayfs/super.c:1691
 legacy_get_tree+0x108/0x220 fs/fs_context.c:661
 vfs_get_tree+0x8e/0x390 fs/super.c:1413
 do_new_mount fs/namespace.c:2791 [inline]
 do_mount+0x13b3/0x1c30 fs/namespace.c:3111
 ksys_mount+0xdb/0x150 fs/namespace.c:3320
 __do_sys_mount fs/namespace.c:3334 [inline]
 __se_sys_mount fs/namespace.c:3331 [inline]
 __x64_sys_mount+0xbe/0x150 fs/namespace.c:3331
 do_syscall_64+0xfd/0x6a0 arch/x86/entry/common.c:296
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x459879
Code: fd b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 0f 83 cb b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f057a912c78 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 0000000000000005 RCX: 0000000000459879
RDX: 00000000200000c0 RSI: 0000000020000000 RDI: 000000000040000a
RBP: 000000000075bfc8 R08: 0000000020000100 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f057a9136d4
R13: 00000000004c5ea4 R14: 00000000004daa08 R15: 00000000ffffffff

The buggy address belongs to the page:
page:ffffea0001ebc640 refcount:0 mapcount:-128 mapping:0000000000000000 index:0x1
flags: 0x1fffc0000000000()
raw: 01fffc0000000000 ffffea00020ce788 ffffea000209a948 0000000000000000
raw: 0000000000000001 0000000000000000 00000000ffffff7f 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88807af18f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88807af19000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff88807af19080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                   ^
 ffff88807af19100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88807af19180: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
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