Fix async stack walk crash for continuations with null DiagnosticIP#128496
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tommcdon merged 2 commits intoMay 23, 2026
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CordbAsyncStackWalk::PopulateFrame() crashes when encountering a continuation whose ResumeInfo.DiagnosticIP is NULL (e.g. the new ValueTaskContinuation introduced in dotnet#127973). GetNativeCodeInfoForAddr is called with a null address which fails. Fix: In PopulateFrame(), skip continuations with diagnosticIP == NULL the same way DiagnosticHidden frames are skipped (advance to Next). Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
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jakobbotsch
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May 22, 2026
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Thanks! Sorry for the break.
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Pull request overview
This PR adjusts CoreCLR debugger async stack walking so that CordbAsyncStackWalk::PopulateFrame() skips continuations that don’t have a diagnostic instruction pointer, preventing downstream native code lookups from being performed on a null/zero address.
Changes:
- Add a guard in
CordbAsyncStackWalk::PopulateFrame()to detectDiagnosticIPbeing null/zero and advance to the next continuation instead of attempting to materialize a debug frame. - Treat these continuations similarly to existing “DiagnosticHidden” continuations by skipping them during frame population.
PCODE is unsigned int on ARM32, so comparing to NULL (std::nullptr_t) is invalid. Use 0 instead. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
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CordbAsyncStackWalk::PopulateFrame() crashes when encountering a continuation whose ResumeInfo.DiagnosticIP is NULL (e.g. the new ValueTaskContinuation introduced in #127973). GetNativeCodeInfoForAddr is called with a null address which fails.
Fix: In PopulateFrame(), skip continuations with diagnosticIP == NULL the same way DiagnosticHidden frames are skipped (advance to Next).