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BUG: KASAN: use-after-free in memset include/linux/string.h:337 [inline]
BUG: KASAN: use-after-free in __ext4_expand_extra_isize+0x16c/0x240 fs/ext4/inode.c:5923
Write of size 4063 at addr ffff88807622f0a0 by task syz-executor1/7700

CPU: 0 PID: 7700 Comm: syz-executor1 Not tainted 5.0.0-rc3+ #41
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+0x1db/0x2d0 lib/dump_stack.c:113
 print_address_description.cold+0x7c/0x20d mm/kasan/report.c:187
 kasan_report.cold+0x1b/0x40 mm/kasan/report.c:317
 check_memory_region_inline mm/kasan/generic.c:185 [inline]
 check_memory_region+0x123/0x190 mm/kasan/generic.c:191
 memset+0x24/0x40 mm/kasan/common.c:113
 memset include/linux/string.h:337 [inline]
 __ext4_expand_extra_isize+0x16c/0x240 fs/ext4/inode.c:5923
 ext4_try_to_expand_extra_isize fs/ext4/inode.c:5975 [inline]
 ext4_mark_inode_dirty+0x827/0xb80 fs/ext4/inode.c:6051
 ext4_dirty_inode+0x8f/0xc0 fs/ext4/inode.c:6085
 __mark_inode_dirty+0xab5/0x1590 fs/fs-writeback.c:2122
 generic_update_time+0x268/0x440 fs/inode.c:1654
 update_time fs/inode.c:1670 [inline]
 touch_atime+0x2a4/0x320 fs/inode.c:1741
 file_accessed include/linux/fs.h:2161 [inline]
 iterate_dir+0x372/0x5f0 fs/readdir.c:56
 __do_sys_getdents fs/readdir.c:231 [inline]
 __se_sys_getdents fs/readdir.c:212 [inline]
 __x64_sys_getdents+0x2ad/0x530 fs/readdir.c:212
 do_syscall_64+0x1a3/0x800 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x45649b
Code: 02 74 b6 31 f6 eb b9 0f 1f 84 00 00 00 00 00 41 57 41 56 48 63 ff 41 55 41 54 b8 4e 00 00 00 55 53 48 89 f3 48 83 ec 08 0f 05 <48> 3d 00 f0 ff ff 77 55 4c 8d 24 06 49 89 c5 4c 39 e6 73 33 90 0f
RSP: 002b:00007fff49fe0c00 EFLAGS: 00000206 ORIG_RAX: 000000000000004e
RAX: ffffffffffffffda RBX: 00000000017a19b0 RCX: 000000000045649b
RDX: 0000000000008000 RSI: 00000000017a19b0 RDI: 0000000000000004
RBP: 00000000017a19b0 R08: 0000000000000000 R09: 000000000000000b
R10: 0000000000000005 R11: 0000000000000206 R12: ffffffffffffffd4
R13: 0000000000000016 R14: 0000000000000000 R15: 0000000000000001

The buggy address belongs to the page:
page:ffffea0001d88bc0 count:2 mapcount:0 mapping:ffff88821a1c9558 index:0x455
def_blk_aops 
flags: 0x1fffc000000203a(referenced|dirty|lru|active|private)
raw: 01fffc000000203a ffffea0001e1c548 ffffea0001f5a048 ffff88821a1c9558
raw: 0000000000000455 ffff888095b190a8 00000002ffffffff ffff88805815a1c0
page dumped because: kasan: bad access detected
page->mem_cgroup:ffff88805815a1c0

Memory state around the buggy address:
 ffff88807622ff00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88807622ff80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff888076230000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                   ^
 ffff888076230080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888076230100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
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