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BUG: KCSAN: data-race in ext4_alloc_da_blocks / ext4_da_reserve_space

write to 0xffff888131c84998 of 4 bytes by task 23188 on cpu 0:
 ext4_da_reserve_space+0x147/0x200 fs/ext4/inode.c:1494
 ext4_insert_delayed_block fs/ext4/inode.c:1660 [inline]
 ext4_da_map_blocks fs/ext4/inode.c:1774 [inline]
 ext4_da_get_block_prep+0x513/0x9a0 fs/ext4/inode.c:1838
 __block_write_begin_int+0x4c5/0x1080 fs/buffer.c:2006
 __block_write_begin+0x2b/0x40 fs/buffer.c:2056
 ext4_da_write_begin+0x4a8/0x7f0 fs/ext4/inode.c:3024
 generic_perform_write+0x1b8/0x3e0 mm/filemap.c:3770
 ext4_buffered_write_iter+0x305/0x400 fs/ext4/file.c:269
 ext4_file_write_iter+0x2e7/0x11f0
 call_write_iter include/linux/fs.h:2163 [inline]
 new_sync_write fs/read_write.c:507 [inline]
 vfs_write+0x7bc/0x900 fs/read_write.c:594
 ksys_write+0xd9/0x190 fs/read_write.c:647
 __do_sys_write fs/read_write.c:659 [inline]
 __se_sys_write fs/read_write.c:656 [inline]
 __x64_sys_write+0x3e/0x50 fs/read_write.c:656
 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 0xffff888131c84998 of 4 bytes by task 23182 on cpu 1:
 ext4_alloc_da_blocks+0x1a/0xd0 fs/ext4/inode.c:3136
 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+0xae/0x130 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+0x156/0x190 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: 0x00000000 -> 0x00000001

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 23182 Comm: syz-executor.2 Not tainted 5.15.0-rc2-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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