Re: [edk2-devel] OVMF is crashing for me in master

["Andrew Fish" <afish@apple.com>]

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Liming,

Thanks for looking into this!

Can someone also answer my question about the expected behavior of taking an exception in OVMF?  Is the CpuDeadloop() expected? 

Thanks,

Andrew Fish

> On Oct 10, 2019, at 6:19 PM, Gao, Liming <liming.gao@intel.com> wrote:
> 
> Andrew:
>   I verify the change (2de1f611be06ded3a59726a4052a9039be7d459b MdeModulePkg/BdsDxe: Also call PlatformBootManagerWaitCallback on 0) in Emulator.
>   It works, because PCD value is set to 10 in Emulator.
>
>   Before this change, if TimeOut PCD is zero, BdsEntry doesn’t call PlatformBootManagerWaitCallback().
>   After this change,  if TimeOut PCD is zero, BdsEntry still call PlatformBootManagerWaitCallback(). So, it trigs this issue. I agree your fix.
>
> Pete:
>   Will you contribute the patch to fix this hang issue in OVMF?
>
> Thanks
> Liming
> From: devel@edk2.groups.io [mailto:devel@edk2.groups.io] On Behalf Of Andrew Fish via Groups.Io
> Sent: Friday, October 11, 2019 5:12 AM
> To: devel@edk2.groups.io; Pete Batard <pete@akeo.ie>
> Subject: [edk2-devel] OVMF is crashing for me in master
>
> This is my flavor of OVMF:  build -p OvmfPkg/OvmfPkgX64.dsc -a X64 -t XCODE5
>
> It looks like I took an exception? Is it expected that an unhandled exception just hang in a dead loop? I would have expected some serial  output about the failure? 
>
> Looks like a divide by zero exception. The exception context has PC and FP so I can manually walk the stack. Yikes I see PlatformBootManagerWaitCallback() will fault if PcdPlatformBootTimeOut is zero? 
> /Volumes/Case/UDK2018(master)>git grep PcdPlatformBootTimeOut -- *.dsc
> ArmVirtPkg/ArmVirtQemu.dsc:194:  gEfiMdePkgTokenSpaceGuid.PcdPlatformBootTimeOut|3
> ArmVirtPkg/ArmVirtQemuKernel.dsc:191:  gEfiMdePkgTokenSpaceGuid.PcdPlatformBootTimeOut|3
> ArmVirtPkg/ArmVirtXen.dsc:122:  gEfiMdePkgTokenSpaceGuid.PcdPlatformBootTimeOut|3
> EmulatorPkg/EmulatorPkg.dsc:236:  gEfiMdePkgTokenSpaceGuid.PcdPlatformBootTimeOut|L"Timeout"|gEfiGlobalVariableGuid|0x0|10
> OvmfPkg/OvmfPkgIa32.dsc:541:  gEfiMdePkgTokenSpaceGuid.PcdPlatformBootTimeOut|0
> OvmfPkg/OvmfPkgIa32X64.dsc:553:  gEfiMdePkgTokenSpaceGuid.PcdPlatformBootTimeOut|0
> OvmfPkg/OvmfPkgX64.dsc:552:  gEfiMdePkgTokenSpaceGuid.PcdPlatformBootTimeOut|0
> OvmfPkg/OvmfXen.dsc:470:  gEfiMdePkgTokenSpaceGuid.PcdPlatformBootTimeOut|0
> UefiPayloadPkg/UefiPayloadPkgIa32.dsc:344:  gEfiMdePkgTokenSpaceGuid.PcdPlatformBootTimeOut|3
> UefiPayloadPkg/UefiPayloadPkgIa32X64.dsc:345:  gEfiMdePkgTokenSpaceGuid.PcdPlatformBootTimeOut|3
> 
> 
> OK PcdPlatformBootTimeOut is zero on Ovmf, so how did this ever work?
> 
> 
> Ahhh gotom.... 
> /Volumes/Case/UDK2018(master)>git blame -L344,344  /Volumes/Case/UDK2018/MdeModulePkg/Universal/BdsDxe/BdsEntry.c 
> 2de1f611be0 (Pete Batard 2019-09-25 23:50:05 +0800 344)   PlatformBootManagerWaitCallback (0);
> 
> 
> This call causes a divide by zero if PcdPlatformBootTimeOut == 0. 
>
> This fixes my crash:
> diff --git a/OvmfPkg/Library/PlatformBootManagerLib/BdsPlatform.c b/OvmfPkg/Library/PlatformBootManagerLib/BdsPlatform.c
> index 70df6b841a..d6ae43e900 100644
> --- a/OvmfPkg/Library/PlatformBootManagerLib/BdsPlatform.c
> +++ b/OvmfPkg/Library/PlatformBootManagerLib/BdsPlatform.c
> @@ -1634,6 +1634,11 @@ PlatformBootManagerWaitCallback (
>    UINT16                              Timeout;
>
>    Timeout = PcdGet16 (PcdPlatformBootTimeOut);
> +  if (Timeout ==  0) {
> +    Timeout = 100;
> +  } else {
> +    Timeout = (Timeout - TimeoutRemain) * 100 / Timeout;
> +  }
>
>    Black.Raw = 0x00000000;
>    White.Raw = 0x00FFFFFF;
> @@ -1643,7 +1648,7 @@ PlatformBootManagerWaitCallback (
>      Black.Pixel,
>      L"Start boot option",
>      White.Pixel,
> -    (Timeout - TimeoutRemain) * 100 / Timeout,
> +    Timeout,
>      0
>      );
>  }
> 
> 
>
> lldb debugger output:
>
> (lldb) bt
> * thread #1, stop reason = signal SIGTRAP
>   * frame #0: 0x0000000007b58a70 CpuDxe.dll:CpuDeadLoop() + 13 at /Volumes/Case/UDK2018/MdePkg/Library/BaseLib/CpuDeadLoop.c:31
>     frame #1: 0x0000000007b61222 CpuDxe.dll:CommonExceptionHandlerWorker() + 674 at /Volumes/Case/UDK2018/UefiCpuPkg/Library/CpuExceptionHandlerLib/PeiDxeSmmCpuException.c:115
>     frame #2: 0x0000000007b61624 CpuDxe.dll:CommonExceptionHandler() + 36 at /Volumes/Case/UDK2018/UefiCpuPkg/Library/CpuExceptionHandlerLib/DxeException.c:40
>     frame #3: 0x0000000007b5ff26 CpuDxe.dll:HasErrorCode() + 230
> (lldb) fr sel 1
> frame #1: 0x0000000007b61222 CpuDxe.dll:CommonExceptionHandlerWorker() + 674 at /Volumes/Case/UDK2018/UefiCpuPkg/Library/CpuExceptionHandlerLib/PeiDxeSmmCpuException.c:115
>    91             (ExternalInterruptHandler[ExceptionType]) (ExceptionType, SystemContext);
>    92           } else if (ExceptionType < CPU_EXCEPTION_NUM) {
>    93             //
>    94             // Get Spinlock to display CPU information
>    95             //
>    96             while (!AcquireSpinLockOrFail (&ExceptionHandlerData->DisplayMessageSpinLock)) {
>    97               CpuPause ();
>    98             }
>    99             //
>    100           // Initialize the serial port before dumping.
>    101           //
>    102           SerialPortInitialize ();
>    103           //
>    104           // Display ExceptionType, CPU information and Image information
>    105           //
>    106           DumpImageAndCpuContent (ExceptionType, SystemContext);
>    107           //
>    108           // Release Spinlock of output message
>    109           //
>    110           ReleaseSpinLock (&ExceptionHandlerData->DisplayMessageSpinLock);
>    111           //
>    112           // Enter a dead loop if needn't to execute old IDT handler further
>    113           //
>    114           if (ReservedVectors[ExceptionType].Attribute != EFI_VECTOR_HANDOFF_HOOK_BEFORE) {
> -> 115            CpuDeadLoop ();
>    116           }
>    117         }
>    118       }
>    119
> (lldb) p ExceptionType
> (EFI_EXCEPTION_TYPE) $0 = 0
> (lldb) p SystemContext.SystemContextX64->Rip
> (UINT64) $1 = 0x0000000007a9cc38
> (lldb) p SystemContext.SystemContextX64->Rbp
> (UINT64) $2 = 0x0000000007e8fc20
> (lldb) efi_backtrace --pc 0x0000000007a9cc38 --frame 0x0000000007e8fc20 --symbols
>   frame  0: 0x07a9cc38 BdsDxe:PlatformBootManagerWaitCallback + 35 at /Volumes/Case/UDK2018/OvmfPkg/Library/PlatformBootManagerLib/BdsPlatform.c:1646:37
>   frame  1: 0x07a9e744 BdsDxe:BdsWait + 269 at /Volumes/Case/UDK2018/MdeModulePkg/Universal/BdsDxe/BdsEntry.c:344:3
>   frame  2: 0x07a9dff9 BdsDxe:BdsEntry + 2620 at /Volumes/Case/UDK2018/MdeModulePkg/Universal/BdsDxe/BdsEntry.c:1002:5
>   frame  3: 0x07eb367d DxeCore:DxeMain + 2680 at /Volumes/Case/UDK2018/MdeModulePkg/Core/Dxe/DxeMain/DxeMain.c:544:3
>   frame  4: 0x07e943cb DxeCore:_ModuleEntryPoint + 20 at /Volumes/Case/UDK2018/MdePkg/Library/DxeCoreEntryPoint/DxeCoreEntryPoint.c:48:3
>   frame  5: 0x07edc947 DxeIpl.dll`AsmEnableCache
>   frame  6: 0x07ee1e4e DxeIpl:HandOffToDxeCore + 509 at /Volumes/Case/UDK2018/MdeModulePkg/Core/DxeIplPeim/X64/DxeLoadFunc.c:113:3
>   frame  7: 0x07ee0604 DxeIpl:DxeLoadCore + 1354 at /Volumes/Case/UDK2018/MdeModulePkg/Core/DxeIplPeim/DxeLoad.c:449:3
>   frame  8: 0x07eeff2f PeiCore.dll`PeiCore.cold.3 + 847
>   frame  9: 0x07ee9d04 PeiCore:PeiCore + 163 at /Volumes/Case/UDK2018/MdeModulePkg/Core/Pei/PeiMain/PeiMain.c:502:3
>   frame 10: 0x0082c387 0x0082c387
>   frame 11: 0x00825dd7 0x00825dd7
>   frame 12: 0x0082ad27 0x0082ad27
>   frame 13: 0x0082b3a8 0x0082b3a8
>   frame 14: 0x0082bf23 0x0082bf23
>   frame 15: 0x00825e24 0x00825e24
>   frame 16: 0x00823af2 0x00823af2
>   frame 17: 0xfffd1db8 SecMain:SecStartupPhase2 + 67 at /Volumes/Case/UDK2018/OvmfPkg/Sec/SecMain.c:858:3
>   frame 18: 0xfffd1d67 SecMain:SecCoreStartupWithStack + 420 at /Volumes/Case/UDK2018/OvmfPkg/Sec/SecMain.c:821:3
>   frame 19: 0xfffd1e14 SecMain:ProcessLibraryConstructorList + 0 at /Volumes/Case/UDK2018/Build/OvmfX64/DEBUG_XCODE5/X64/OvmfPkg/Sec/SecMain/DEBUG/AutoGen.c:201
>
> (lldb) l /Volumes/Case/UDK2018/OvmfPkg/Library/PlatformBootManagerLib/BdsPlatform.c:1646
>    1646         (Timeout - TimeoutRemain) * 100 / Timeout,
>    1647         0
>    1648         );
>    1649     }
>    1650
>    1651     /**
>    1652       The function is called when no boot option could be launched,
>    1653       including platform recovery options and options pointing to applications
>    1654       built into firmware volumes.
>    1655
> (lldb) l /Volumes/Case/UDK2018/MdeModulePkg/Universal/BdsDxe/BdsEntry.c:344
>    344         PlatformBootManagerWaitCallback (0);
>    345         DEBUG ((EFI_D_INFO, "[Bds]Exit the waiting!\n"));
>    346       }
>    347
>    348       /**
>    349         Attempt to boot each boot option in the BootOptions array.
>    350
>    351         @param BootOptions       Input boot option array.
>    352         @param BootOptionCount   Input boot option count.
>    353         @param BootManagerMenu   Input boot manager menu.
>    354
>
>
> Thanks,
>
> Andrew Fish
>
> 


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