Re: [MdeModulePkg] SetVirtualAddressMap() crashed due to DxeReportStatusCodeLib assuming the state of the BootService Memory at runtime.

[Andrew Fish <afish@apple.com>]

> On Aug 8, 2016, at 6:21 PM, Zeng, Star <star.zeng@intel.com> wrote:
> 
> Andrew,
> 
> Should MdeModulePkg/Library/RuntimeDxeReportStatusCodeLib be used for your case if there are really runtime status code reporting needed?
> 

Star,

If the Library instance does not fully support DXE_RUNTIME_DRIVER, why is it listed in the LIBRARY_CLASS as supported? 

https://github.com/tianocore/edk2/blob/master/MdeModulePkg/Library/DxeReportStatusCodeLib/DxeReportStatusCodeLib.inf#L25

 LIBRARY_CLASS                  = ReportStatusCodeLib|DXE_CORE DXE_DRIVER DXE_RUNTIME_DRIVER DXE_SAL_DRIVER DXE_SMM_DRIVER UEFI_APPLICATION UEFI_DRIVER SMM_CORE

Actually I tried to add the UefiRuntimeDriverLib and the build failed as UefiRuntimeDriverLib was not supported for the DXE_CORE type. Maybe the bug is this library instance lists DXE_RUNTIME_DRIVER,  DXE_SAL_DRIVER and DXE_SMM_DRIVER when it has special case code to support DXE_CORE? Maybe this library is trying to do too many things? 

What ReportStatusCodeLib would you recommend to link with RuntimeDxe driver: https://github.com/tianocore/edk2/blob/master/MdeModulePkg/Core/RuntimeDxe/RuntimeDxe.inf

Thanks,

Andrew Fish

> Thanks,
> Star
> -----Original Message-----
> From: edk2-devel [mailto:edk2-devel-bounces@lists.01.org] On Behalf Of Andrew Fish
> Sent: Tuesday, August 9, 2016 7:08 AM
> To: edk2-devel <edk2-devel@lists.01.org>
> Subject: [edk2] [MdeModulePkg] SetVirtualAddressMap() crashed due to DxeReportStatusCodeLib assuming the state of the BootService Memory at runtime.
> 
> I was messing about with an ExitBootServices test that fills boot services memory with 0xAFAFAFAFAFAFAFAF (It was Vincent's idea to use my Initials but it has the handy property of being a non-cononical address and causes on GP fault on X64) and SetVirtualAddressMap() started crashing. 
> 
> It looks like this code is assuming the 1st call to ReportStatus code will not happen at runtime. This is not the case for the RuntimeDxe driver. 
> https://github.com/tianocore/edk2/blob/master/MdeModulePkg/Library/DxeReportStatusCodeLib/ReportStatusCodeLib.c#L43
> VOID
> InternalGetReportStatusCode (
> VOID
> )
> {
> EFI_STATUS  Status;
> 
> if (mReportStatusCodeLibStatusCodeProtocol != NULL) {
>   return;
> }
> 
> //
> // Check gBS just in case ReportStatusCode is called before gBS is initialized.
> //
> if (gBS != NULL && gBS->LocateProtocol != NULL) {
>   Status = gBS->LocateProtocol (&gEfiStatusCodeRuntimeProtocolGuid, NULL, (VOID**) &mReportStatusCodeLibStatusCodeProtocol);
>   if (EFI_ERROR (Status)) {
>     mReportStatusCodeLibStatusCodeProtocol = NULL;
>   }
> }
> }
> 
> I'm guessing this seems to work due to:https://github.com/tianocore/edk2/blob/master/MdeModulePkg/Core/Dxe/DxeMain/DxeMain.c#L803
> 
> //
> // Zero out the Boot Service Table
> //
> ZeroMem (gBS, sizeof (EFI_BOOT_SERVICES));
> 
> 
> Thus if I'm looking at this code correctly it only looks like it works at Runtime since it is depending on the value of a boot services memory buffer not changing. This is not a valid assumption as that code is owned by the caller of ExitBootServices, so it should be legal for my test to change the value. 
> 
> I wanted to get a few more eyes on this prior to filling a bug?
> 
> Thanks,
> 
> Andrew Fish
> 
> 
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