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Use CopyContext to restore saved context on X86 #65490

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Merged
VSadov merged 3 commits into from
Feb 18, 2022
Merged

Use CopyContext to restore saved context on X86 #65490

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Use CopyContext to restore saved context on X86
VSadov Feb 17, 2022
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VSadov Feb 18, 2022
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VSadov Feb 18, 2022
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18 changes: 17 additions & 1 deletion src/coreclr/vm/threadsuspend.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -2509,6 +2509,18 @@ void RedirectedThreadFrame::ExceptionUnwind()
#ifndef TARGET_UNIX

#ifdef TARGET_X86

// a helper to make sure these calls are not inlined into a filter function.
// in particular we do not want a possibility of inlined destructor calls.
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@jkotas jkotas Feb 18, 2022

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This should not be a concern once you change it to EEPOLICY_HANDLE_FATAL_ERROR. EEPOLICY_HANDLE_FATAL_ERROR is non-inlineable.

NOINLINE void CopyContextHelper(CONTEXT* pTarget, CONTEXT* pCtx)
{
if (!CopyContext(pTarget, pTarget->ContextFlags, pCtx))
{
STRESS_LOG1(LF_SYNC, LL_ERROR, "ERROR: Could not set context record, lastError = 0x%x\n", GetLastError());
ThrowLastError();
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@jkotas jkotas Feb 18, 2022

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Suggested change
ThrowLastError();
EEPOLICY_HANDLE_FATAL_ERROR(COR_E_EXECUTIONENGINE);

The caller does not expect exceptions. This needs to be failfast. Throwing exception is likely going to lead to hard to diagnose crash otherwise.

}
}

//****************************************************************************************
// This will check who caused the exception. If it was caused by the the redirect function,
// the reason is to resume the thread back at the point it was redirected in the first
Expand Down Expand Up @@ -2577,7 +2589,11 @@ int RedirectedHandledJITCaseExceptionFilter(
pFrame->Pop();

// Copy the saved context record into the EH context;
ReplaceExceptionContextRecord(pExcepPtrs->ContextRecord, pCtx);
// NB: cannot use ReplaceExceptionContextRecord here.
// these contexts may contain extended registers and may have different format
// for reasons such as alignment or context compaction
CONTEXT* pTarget = pExcepPtrs->ContextRecord;
CopyContextHelper(pTarget, pCtx);

DWORD espValue = pCtx->Esp;

Expand Down