==================================================================
BUG: KCSAN: data-race in ext4_mark_iloc_dirty / ext4_writepages

write to 0xffff8881257f2a40 of 8 bytes by task 24237 on cpu 1:
 mpage_map_and_submit_extent fs/ext4/inode.c:2477 [inline]
 ext4_writepages+0x12b9/0x1d40 fs/ext4/inode.c:2772
 do_writepages+0x6b/0x170 mm/page-writeback.c:2344
 __filemap_fdatawrite_range+0x1c5/0x230 mm/filemap.c:421
 __filemap_fdatawrite mm/filemap.c:429 [inline]
 filemap_flush+0x2d/0x40 mm/filemap.c:456
 ext4_alloc_da_blocks+0x78/0x180 fs/ext4/inode.c:3146
 ext4_ioctl+0xf0d/0x32b0 fs/ext4/ioctl.c:1045
 vfs_ioctl fs/ioctl.c:47 [inline]
 ksys_ioctl+0x109/0x150 fs/ioctl.c:763
 __do_sys_ioctl fs/ioctl.c:772 [inline]
 __se_sys_ioctl fs/ioctl.c:770 [inline]
 __x64_sys_ioctl+0x4c/0x60 fs/ioctl.c:770
 do_syscall_64+0xcc/0x3a0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff8881257f2a40 of 8 bytes by task 24224 on cpu 0:
 ext4_do_update_inode fs/ext4/inode.c:4973 [inline]
 ext4_mark_iloc_dirty+0x810/0x1580 fs/ext4/inode.c:5578
 ext4_mark_inode_dirty+0xe9/0x420 fs/ext4/inode.c:5771
 ext4_dirty_inode+0xb1/0xe0 fs/ext4/inode.c:5802
 __mark_inode_dirty+0x5d4/0x940 fs/fs-writeback.c:2258
 mark_inode_dirty include/linux/fs.h:2183 [inline]
 generic_write_end+0x1b7/0x1f0 fs/buffer.c:2199
 ext4_da_write_end+0x158/0x620 fs/ext4/inode.c:3092
 generic_perform_write+0x1d3/0x320 mm/filemap.c:3298
 ext4_buffered_write_iter+0x143/0x290 fs/ext4/file.c:270
 ext4_file_write_iter+0xfa/0xd70 fs/ext4/file.c:642
 call_write_iter include/linux/fs.h:1901 [inline]
 new_sync_write+0x388/0x4a0 fs/read_write.c:483
 __vfs_write+0xb1/0xc0 fs/read_write.c:496
 vfs_write fs/read_write.c:558 [inline]
 vfs_write+0x18a/0x390 fs/read_write.c:542
 ksys_write+0xd5/0x1b0 fs/read_write.c:611
 __do_sys_write fs/read_write.c:623 [inline]
 __se_sys_write fs/read_write.c:620 [inline]
 __x64_sys_write+0x4c/0x60 fs/read_write.c:620
 do_syscall_64+0xcc/0x3a0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 24224 Comm: syz-executor.5 Not tainted 5.6.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================