==================================================================
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 58896 at addr ffff8880767b91a0 by task syz-executor2/11431

CPU: 1 PID: 11431 Comm: syz-executor2 Not tainted 5.0.0-rc3+ #43
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
 add_dirent_to_buf+0x446/0x6e0 fs/ext4/namei.c:1891
 ext4_add_entry+0x694/0xc60 fs/ext4/namei.c:2084
 ext4_add_nondir+0x28/0x90 fs/ext4/namei.c:2413
 ext4_symlink+0x75c/0xee0 fs/ext4/namei.c:3165
 vfs_symlink fs/namei.c:4126 [inline]
 vfs_symlink+0x378/0x5d0 fs/namei.c:4112
 do_symlinkat+0x239/0x2c0 fs/namei.c:4153
 __do_sys_symlink fs/namei.c:4172 [inline]
 __se_sys_symlink fs/namei.c:4170 [inline]
 __x64_sys_symlink+0x59/0x80 fs/namei.c:4170
 do_syscall_64+0x1a3/0x800 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x457dc7
Code: 0f 1f 00 b8 5c 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 2d ba fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 b8 58 00 00 00 0f 05 <48> 3d 01 f0 ff ff 0f 83 0d ba fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fff1071cab8 EFLAGS: 00000206 ORIG_RAX: 0000000000000058
RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 0000000000457dc7
RDX: 00007fff1071cb37 RSI: 00000000004bd896 RDI: 00007fff1071cb20
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000017
R10: 0000000000000075 R11: 0000000000000206 R12: 0000000000000000
R13: 0000000000000001 R14: 00000000000006d1 R15: 0000000000000002

The buggy address belongs to the page:
page:ffffea0001d9ee40 count:2 mapcount:0 mapping:ffff88809ac37518 index:0x42c
def_blk_aops 
flags: 0x1fffc000000203a(referenced|dirty|lru|active|private)
raw: 01fffc000000203a ffffea00016f9148 ffffea0002316e48 ffff88809ac37518
raw: 0000