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BUG: KCSAN: data-race in ext4_alloc_da_blocks / ext4_da_reserve_space

write to 0xffff888105ed9d60 of 4 bytes by task 23650 on cpu 0:
 ext4_da_reserve_space+0x147/0x200 fs/ext4/inode.c:1491
 ext4_insert_delayed_block fs/ext4/inode.c:1656 [inline]
 ext4_da_map_blocks fs/ext4/inode.c:1770 [inline]
 ext4_da_get_block_prep+0x512/0x9b0 fs/ext4/inode.c:1834
 __block_write_begin_int+0x4a2/0x1060 fs/buffer.c:2011
 __block_write_begin+0x2b/0x40 fs/buffer.c:2061
 ext4_da_write_begin+0x4c8/0x820 fs/ext4/inode.c:3018
 generic_perform_write+0x196/0x3a0 mm/filemap.c:3676
 ext4_buffered_write_iter+0x2f2/0x3f0 fs/ext4/file.c:269
 ext4_file_write_iter+0x2e7/0x11d0 fs/ext4/file.c:519
 call_write_iter include/linux/fs.h:2116 [inline]
 new_sync_write fs/read_write.c:518 [inline]
 vfs_write+0x69d/0x770 fs/read_write.c:605
 ksys_write+0xce/0x180 fs/read_write.c:658
 __do_sys_write fs/read_write.c:670 [inline]
 __se_sys_write fs/read_write.c:667 [inline]
 __x64_sys_write+0x3e/0x50 fs/read_write.c:667
 do_syscall_64+0x4a/0x90 arch/x86/entry/common.c:47
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff888105ed9d60 of 4 bytes by task 23654 on cpu 1:
 ext4_alloc_da_blocks+0x1d/0xd0 fs/ext4/inode.c:3130
 __ext4_ioctl fs/ext4/ioctl.c:991 [inline]
 ext4_ioctl+0xa81/0x1df0 fs/ext4/ioctl.c:1224
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:1069 [inline]
 __se_sys_ioctl+0xcb/0x140 fs/ioctl.c:1055
 __x64_sys_ioctl+0x3f/0x50 fs/ioctl.c:1055
 do_syscall_64+0x4a/0x90 arch/x86/entry/common.c:47
 entry_SYSCALL_64_after_hwframe+0x44/0xae

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 23654 Comm: syz-executor.1 Not tainted 5.12.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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