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Fix x86 DAC stack walk regression from Environment.CallEntryPoint skip #127199

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Merged
tommcdon merged 2 commits into from
Apr 22, 2026
+8 −19
Merged

Fix x86 DAC stack walk regression from Environment.CallEntryPoint skip #127199

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dad7203
Fix x86 DAC stack walk regression from Environment.CallEntryPoint skip
tommcdon Apr 20, 2026
ac3c73c
Remove continue skips for EH frames in UnwindStackWalkFrame
tommcdon Apr 21, 2026
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27 changes: 8 additions & 19 deletions src/coreclr/debug/daccess/dacdbiimplstackwalk.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -297,24 +297,12 @@ HRESULT STDMETHODCALLTYPE DacDbiInterfaceImpl::UnwindStackWalkFrame(StackWalkHan
}
else if (pIter->GetFrameState() == StackFrameIterator::SFITER_FRAMELESS_METHOD)
{
MethodDesc *pMD = pIter->m_crawl.GetFunction();
MethodTable *pMT = pMD->GetMethodTable();

// Skip the exception handling managed code, the debugger clients are not supposed to see them
// EH.DispatchEx, EH.RhThrowEx, EH.RhThrowHwEx, ExceptionServices.InternalCalls.SfiInit, ExceptionServices.InternalCalls.SfiNext
// and System.Runtime.StackFrameIterator.*
if (pMT == g_pEHClass || pMT == g_pExceptionServicesInternalCallsClass || pMT == g_pStackFrameIteratorClass)
{
continue;
}

// Skip the runtime helper that invokes the main program entrypoint, the debuggers do not want to see it.
// Environment.CallEntryPoint
if (pMD == g_pEnvironmentCallEntryPointMethodDesc)
{
continue;
}

// Runtime-internal frames (exception handling helpers, entry point, etc.) are NOT
// skipped here with continue. On x86, GetFrameWorker() unwinds one frame ahead to
// compute the frame pointer (see rsstackwalk.cpp). Skipping frames here would cause
// the unwind to land on the wrong frame, producing incorrect frame pointers.
// Instead, GetStackWalkCurrentFrameInfo classifies these frames and GetFrameWorker
// returns S_FALSE to hide them from debugger clients.
fIsAtEndOfStack = FALSE;
}
else
Expand Down Expand Up @@ -425,7 +413,8 @@ HRESULT STDMETHODCALLTYPE DacDbiInterfaceImpl::GetStackWalkCurrentFrameInfo(Stac
{
MethodDesc *pMD = pIter->m_crawl.GetFunction();
// EH.DispatchEx, EH.RhThrowEx, EH.RhThrowHwEx, ExceptionServices.InternalCalls.SfiInit, ExceptionServices.InternalCalls.SfiNext
if (pMD->GetMethodTable() == g_pEHClass || pMD->GetMethodTable() == g_pExceptionServicesInternalCallsClass)
// and System.Runtime.StackFrameIterator.*
if (pMD->GetMethodTable() == g_pEHClass || pMD->GetMethodTable() == g_pExceptionServicesInternalCallsClass || pMD->GetMethodTable() == g_pStackFrameIteratorClass)
{
ftResult = kManagedExceptionHandlingCodeFrame;
}
Expand Down
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