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Fix native memory leak in AsAnyMarshaler.ConvertLayoutToNative on exception #126909

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Fix native memory leak in AsAnyMarshaler.ConvertLayoutToNative on exception #126909

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Copilot Apr 14, 2026
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Fix native memory leak in AsAnyMarshaler.ConvertLayoutToNative
Copilot Apr 14, 2026
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jkoritzinsky Apr 14, 2026
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13 changes: 11 additions & 2 deletions src/coreclr/System.Private.CoreLib/src/System/StubHelpers.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -1265,9 +1265,18 @@ private unsafe IntPtr ConvertLayoutToNative(object pManagedHome, int dwFlags)
IntPtr pNativeHome = Marshal.AllocCoTaskMem(allocSize);

// marshal the object as class with layout (UnmanagedType.LPStruct)
if (IsIn(dwFlags))
try
{
if (IsIn(dwFlags))
{
StubHelpers.LayoutTypeConvertToUnmanaged(pManagedHome, (byte*)pNativeHome, ref cleanupWorkList);
}
}
catch
{
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StubHelpers.LayoutTypeConvertToUnmanaged(pManagedHome, (byte*)pNativeHome, ref cleanupWorkList);
StubHelpers.DestroyCleanupList(ref cleanupWorkList);
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@AaronRobinsonMSFT AaronRobinsonMSFT Apr 23, 2026

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Is the full clean-up always safe here? I'd assume that there are already clean-up places for this. The FreeCoTaskMem makes sense, but do we really need the StubHelpers.DestroyCleanupList() as well?

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@jkoritzinsky jkoritzinsky Apr 24, 2026

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We don't technically "need" the cleanup list cleanup as the only entries (SafeHandle instances) will eventually be finalized, but without this, they'd have a mismatched refcount until finalization.

Marshal.FreeCoTaskMem(pNativeHome);
throw;
}
if (IsOut(dwFlags))
{
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