On 10/11/19 06:59, Andrew Fish via Groups.Io wrote: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?
Yes, it is.The exception handler dumps the register file and the stack to theemulated serial port, not to the QEMU debug port.When looking for OVMF debug messages, people usually (and rightly) checkwherever the QEMU debug port has been redirected. (Unless they builtOVMF with -D DEBUG_ON_SERIAL_PORT.) However, the exception handleralways dumps the state to the serial port, regardless ofDEBUG_ON_SERIAL_PORT. This can be confusing, as the normally consulteddebug log has no indication of the issue.
Laszlo,
Thanks if I add -serial file:serial.log to the QEMU command line I see the exception in serial.log.
Thanks,
Andrew Fish
ThanksLaszlo
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