==================================================================
BUG: KCSAN: data-race in ext4_alloc_da_blocks / ext4_da_reserve_space

write to 0xffff888106628c38 of 4 bytes by task 7786 on cpu 0:
 ext4_da_reserve_space+0x132/0x270 fs/ext4/inode.c:1468
 ext4_insert_delayed_block fs/ext4/inode.c:1631 [inline]
 ext4_da_map_blocks fs/ext4/inode.c:1746 [inline]
 ext4_da_get_block_prep+0x87e/0xa50 fs/ext4/inode.c:1810
 ext4_block_write_begin+0x336/0xbd0 fs/ext4/inode.c:1053
 ext4_da_write_begin+0x220/0xa10 fs/ext4/inode.c:2995
 generic_perform_write+0x13a/0x320 mm/filemap.c:3302
 ext4_buffered_write_iter+0x14e/0x280 fs/ext4/file.c:270
 ext4_file_write_iter+0xf4/0xd30 fs/ext4/file.c:642
 call_write_iter include/linux/fs.h:1907 [inline]
 new_sync_write+0x303/0x400 fs/read_write.c:484
 __vfs_write+0x9e/0xb0 fs/read_write.c:497
 vfs_write fs/read_write.c:559 [inline]
 vfs_write+0x189/0x380 fs/read_write.c:543
 ksys_write+0xc5/0x1a0 fs/read_write.c:612
 __do_sys_write fs/read_write.c:624 [inline]
 __se_sys_write fs/read_write.c:621 [inline]
 __x64_sys_write+0x49/0x60 fs/read_write.c:621
 do_syscall_64+0xc7/0x3b0 arch/x86/entry/common.c:295
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff888106628c38 of 4 bytes by task 7790 on cpu 1:
 ext4_alloc_da_blocks+0x48/0x170 fs/ext4/inode.c:3110
 ext4_ioctl+0xf42/0x3340 fs/ext4/ioctl.c:1033
 vfs_ioctl fs/ioctl.c:47 [inline]
 ksys_ioctl+0x101/0x150 fs/ioctl.c:763
 __do_sys_ioctl fs/ioctl.c:772 [inline]
 __se_sys_ioctl fs/ioctl.c:770 [inline]
 __x64_sys_ioctl+0x47/0x60 fs/ioctl.c:770
 do_syscall_64+0xc7/0x3b0 arch/x86/entry/common.c:295
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 7790 Comm: syz-executor.0 Not tainted 5.7.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================