https://github.com/haiku/haiku/blob/master/src/system/kernel/vm/vm.cpp#LL3811C1-L3817C3

```cpp
	VMArea* area = locker.AddressSpace()->LookupArea(address);
	if (area != NULL) {
		if (!kernel && (area->protection & (B_READ_AREA | B_WRITE_AREA)) == 0)
			return B_ERROR;

		return area->id;
	}
```

Why is this the case?