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BUG: KASAN: use-after-free in ext4_xattr_set_entry+0x2f69/0x3d80 fs/ext4/xattr.c:1602
Read of size 4 at addr ffff88818fa84083 by task syz-executor1/3653

CPU: 0 PID: 3653 Comm: syz-executor1 Not tainted 4.20.0-rc2+ #336
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+0x244/0x39d lib/dump_stack.c:113
 print_address_description.cold.7+0x9/0x1ff mm/kasan/report.c:256
 kasan_report_error mm/kasan/report.c:354 [inline]
 kasan_report.cold.8+0x242/0x309 mm/kasan/report.c:412
 __asan_report_load4_noabort+0x14/0x20 mm/kasan/report.c:432
 ext4_xattr_set_entry+0x2f69/0x3d80 fs/ext4/xattr.c:1602
 ext4_xattr_ibody_set+0x81/0x2b0 fs/ext4/xattr.c:2242
 ext4_xattr_set_handle+0xb8f/0x16c0 fs/ext4/xattr.c:2398
 __ext4_set_acl+0x60e/0x740 fs/ext4/acl.c:214
 ext4_set_acl+0x30d/0x5a0 fs/ext4/acl.c:254
 set_posix_acl+0x22f/0x2e0 fs/posix_acl.c:874
 posix_acl_xattr_set+0x92/0x140 fs/posix_acl.c:892
 __vfs_setxattr+0x124/0x180 fs/xattr.c:149
 __vfs_setxattr_noperm+0x11d/0x410 fs/xattr.c:180
 vfs_setxattr+0xd8/0x100 fs/xattr.c:223
 setxattr+0x2ea/0x450 fs/xattr.c:450
 path_setxattr+0x1e3/0x230 fs/xattr.c:469
 __do_sys_lsetxattr fs/xattr.c:491 [inline]
 __se_sys_lsetxattr fs/xattr.c:487 [inline]
 __x64_sys_lsetxattr+0xc1/0x150 fs/xattr.c:487
 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x457569
Code: fd b3 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 b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f0ff6c16c78 EFLAGS: 00000246 ORIG_RAX: 00000000000000bd
RAX: ffffffffffffffda RBX: 0000000000000005 RCX: 0000000000457569
RDX: 0000000020000a00 RSI: 00000000200001c0 RDI: 0000000020000180
RBP: 000000000072bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000000000ac R11: 0000000000000246 R12: 00007f0ff6c176d4
R13: 00000000004c29e6 R14: 00000000004d3f78 R15: 00000000ffffffff

The buggy address belongs to the page:
page:ffffea00063ea100 count:0 mapcount:-128 mapping:0000000000000000 index:0x1
flags: 0x2fffc0000000000()
raw: 02fffc0000000000 ffffea00063c7f08 ffffea00064ecd08 0000000000000000
raw: 0000000000000001 0000000000000002 00000000ffffff7f 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88818fa83f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88818fa84000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff88818fa84080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                   ^
 ffff88818fa84100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88818fa84180: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
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