Re: Does a double Page free report "ConvertPages: Incompatible memory types", maybe we could do better.

["Zeng, Star" <star.zeng@intel.com>]

Andrew,

Another path may hit this DEBUG message is AllocatePages() by AllocateAddress type.
I think it is a good suggestion to enhance the DEBUG message. How about the update like below?

-        DEBUG ((DEBUG_ERROR | DEBUG_PAGE, "ConvertPages: Incompatible memory types\n"));
+        DEBUG ((DEBUG_ERROR | DEBUG_PAGE, "ConvertPages: Incompatible memory types, "));
+        if (Entry->Type == EfiConventionalMemory) {
+          DEBUG ((DEBUG_ERROR | DEBUG_PAGE, "the pages to free have been freed\n"));
+        } else {
+          DEBUG ((DEBUG_ERROR | DEBUG_PAGE, "the pages to allocate have been allocated\n"));
+        }


Thanks,
Star
-----Original Message-----
From: edk2-devel [mailto:edk2-devel-bounces@lists.01.org] On Behalf Of Andrew Fish
Sent: Thursday, August 10, 2017 9:04 AM
To: edk2-devel <edk2-devel@lists.01.org>
Subject: [edk2] Does a double Page free report "ConvertPages: Incompatible memory types", maybe we could do better.

It looks to me like if you Free pages, after you free pages you hit this DEBUG message. 


https://github.com/tianocore/edk2/blob/master/MdeModulePkg/Core/Dxe/Mem/Page.c#L790

      if (!(NewType == EfiConventionalMemory ? 1 : 0) ^ (Entry->Type == EfiConventionalMemory ? 1 : 0)) {
        DEBUG ((DEBUG_ERROR | DEBUG_PAGE, "ConvertPages: Incompatible memory types\n"));
        return EFI_NOT_FOUND;
      }

I'm not sure I've thought out all the paths, but would it make more sense if you are trying to convert EfiConventionalMemory to EfiConventionalMemory that you are trying to free pages that are already freed. That is not very obvious from the above DEBUG print.  Could there be an if in the error path to print a better DEBUG message for a free pages bug? 

Also to be pedantic the function change names to: CoreConvertPagesEx(). 

Thanks,


Andrew Fish



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