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BUG: KCSAN: data-race in ext4_alloc_da_blocks / ext4_da_reserve_space

write to 0xffff88813a82f958 of 4 bytes by task 27470 on cpu 0:
 ext4_da_reserve_space+0x12b/0x1f0 fs/ext4/inode.c:1478
 ext4_insert_delayed_block fs/ext4/inode.c:1645 [inline]
 ext4_da_map_blocks fs/ext4/inode.c:1766 [inline]
 ext4_da_get_block_prep+0x49a/0x970 fs/ext4/inode.c:1830
 __block_write_begin_int+0x4c5/0x1010 fs/buffer.c:2010
 __block_write_begin+0x2b/0x40 fs/buffer.c:2060
 ext4_da_write_begin+0x34e/0x590 fs/ext4/inode.c:2972
 generic_perform_write+0x1c8/0x400 mm/filemap.c:3748
 ext4_buffered_write_iter+0x25b/0x380 fs/ext4/file.c:269
 ext4_file_write_iter+0x2e7/0x1200
 call_write_iter include/linux/fs.h:2162 [inline]
 new_sync_write fs/read_write.c:503 [inline]
 vfs_write+0x7f5/0x950 fs/read_write.c:590
 ksys_write+0xd9/0x190 fs/read_write.c:643
 __do_sys_write fs/read_write.c:655 [inline]
 __se_sys_write fs/read_write.c:652 [inline]
 __x64_sys_write+0x3e/0x50 fs/read_write.c:652
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff88813a82f958 of 4 bytes by task 26549 on cpu 1:
 ext4_alloc_da_blocks+0x1a/0x100 fs/ext4/inode.c:3072
 ext4_release_file+0x5b/0x1d0 fs/ext4/file.c:141
 __fput+0x295/0x520 fs/file_table.c:280
 ____fput+0x11/0x20 fs/file_table.c:313
 task_work_run+0x8e/0x110 kernel/task_work.c:164
 tracehook_notify_resume include/linux/tracehook.h:189 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:175 [inline]
 exit_to_user_mode_prepare+0x160/0x190 kernel/entry/common.c:207
 __syscall_exit_to_user_mode_work kernel/entry/common.c:289 [inline]
 syscall_exit_to_user_mode+0x20/0x40 kernel/entry/common.c:300
 do_syscall_64+0x50/0xa0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x00000547 -> 0x00000548

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 26549 Comm: syz-executor.4 Tainted: G        W         5.15.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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