Re: [PATCH v5 0/1] MR824: ntoskrnl: Implement KeGetCurrentProcessorNumberEx

[Jinoh Kang (＠iamahuman)]

Jinoh Kang (@iamahuman) commented about dlls/ntoskrnl.exe/ntoskrnl.c:
> +/***********************************************************************
> -
> -
>      KeGetCurrentProcessorNumberEx   (NTOSKRNL.EXE.@)
> - */
>
> +ULONG WINAPI KeGetCurrentProcessorNumberEx(PPROCESSOR_NUMBER process_number)
> +{
> - FIXME("%p semi-stub\n", process_number);
> -
> - if (process_number)
> - {
> -
>    process_number->Group = 0;
> -
>    process_number->Reserved = 0;
> -
>    process_number->Number = NtGetCurrentProcessorNumber();
> - }
> -
> - return NtGetCurrentProcessorNumber();

You should only call `NtGetCurrentProcessorNumber()` once.  Otherwise, the processor number can change if the thread is preempted and then re-scheduled to another processor.  This leads to inconsistent values between the return value and the `process_number->Number` output.

In general, you should treat `NtGetCurrentProcessorNumber()` as being volatile.