audit: type=1400 audit(1540296226.845:12249): avc:  denied  { map } for  pid=22907 comm="blkid" path="/lib/x86_64-linux-gnu/libuuid.so.1.3.0" dev="sda1" ino=2819 scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:object_r:file_t:s0 tclass=file permissive=1
EXT4-fs error (device sda1): ext4_find_dest_de:1797: inode #16552: block 9779: comm syz-executor2: bad entry in directory: rec_len is smaller than minimal - offset=0, inode=0, rec_len=0, name_len=0, size=4096
EXT4-fs error (device sda1): ext4_xattr_set_entry:1602: inode #16484: comm syz-executor2: corrupted xattr entries
==================================================================
BUG: KASAN: use-after-free in memset include/linux/string.h:329 [inline]
BUG: KASAN: use-after-free in __ext4_expand_extra_isize.isra.13+0x108/0x1b0 fs/ext4/inode.c:5780
Write of size 4063 at addr ffff8801ae0c56a0 by task syz-executor0/6155

CPU: 0 PID: 6155 Comm: syz-executor0 Not tainted 4.14.78+ #23
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0xb9/0x11b lib/dump_stack.c:53
 print_address_description+0x60/0x22b mm/kasan/report.c:252
 kasan_report_error mm/kasan/report.c:351 [inline]
 kasan_report.cold.6+0x11b/0x2dd mm/kasan/report.c:409
 memset+0x1f/0x40 mm/kasan/kasan.c:285
 memset include/linux/string.h:329 [inline]
 __ext4_expand_extra_isize.isra.13+0x108/0x1b0 fs/ext4/inode.c:5780
 ext4_try_to_expand_extra_isize fs/ext4/inode.c:5832 [inline]
 ext4_mark_inode_dirty+0x46c/0x7e0 fs/ext4/inode.c:5908
 ext4_evict_inode+0x69a/0x1520 fs/ext4/inode.c:282
 evict+0x2cb/0x5f0 fs/inode.c:554
 iput_final fs/inode.c:1516 [inline]
 iput+0x373/0x8e0 fs/inode.c:1543
 dentry_unlink_inode+0x25c/0x310 fs/dcache.c:387
 __dentry_kill+0x31b/0x590 fs/dcache.c:591
 dentry_kill fs/dcache.c:632 [inline]
 dput.part.6+0x4b5/0x710 fs/dcache.c:847
 dput+0x1b/0x30 fs/dcache.c:811
 __fput+0x42c/0x6f0 fs/file_table.c:228
 task_work_run+0x116/0x190 kernel/task_work.c:113
 exit_task_work include/linux/task_work.h:22 [inline]
 do_exit+0x8f8/0x2800 kernel/exit.c:865
 do_group_exit+0x100/0x2e0 kernel/exit.c:968
 get_signal+0x4e5/0x1470 kernel/signal.c:2348
 do_signal+0x8f/0x1660 arch/x86/kernel/signal.c:809
 exit_to_usermode_loop+0x116/0x150 arch/x86/entry/common.c:159
 prepare_exit_to_usermode arch/x86/entry/common.c:198 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:267 [inline]
 do_syscall_64+0x35d/0x4b0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x457569
RSP: 002b:00007f0fe9e7dcf8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 000000000072bf08 RCX: 0000000000457569
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 000000000072bf08
RBP: 000000000072bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000072bf0c
R13: 00007fff8416219f R14: 00007f0fe9e7e9c0 R15: 0000000000000000

The buggy address belongs to the page:
page:ffffea0006b83140 count:2 mapcount:0 mapping:ffff8801d9aa8950 index:0x42a
flags: 0x4000000000001074(referenced|dirty|lru|active|private)
raw: 4000000000001074 ffff8801d9aa8950 000000000000042a 00000002ffffffff
raw: ffffea0007315ba0 ffffea00073154a0 ffff8801d52d4b28 ffff8801da81aa80
page dumped because: kasan: bad access detected
page->mem_cgroup:ffff8801da81aa80

Memory state around the buggy address:
 ffff8801ae0c5f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8801ae0c5f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff8801ae0c6000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                   ^
 ffff8801ae0c6080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff8801ae0c6100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================