Crash: access violation in coreclr!PgoManager::getPgoInstrumentationResults during tier-1 background JIT (Windows x86)

[lewing]

Build Information

Build: https://dev.azure.com/dnceng-public/public/_build/results?buildId=1613037
Build error leg or test failing: Build windows-x86 release CoreCLR_AllSubsets-System.Private.Xml.Tests
Pull request: #134676

Also seen on main (same frame, Windows x86 Release CoreCLR): Helix jobs 98eb605a-92e7-45bd-91e3-38e51ec14951 (System.Transactions.Local.Tests), 4749098d-8bf3-4bfe-b8fb-7e0f16da0fa0 (System.Collections.Concurrent.Tests), 3fdcb624-6a07-465c-a3de-068849c7ea6f (System.Resources.Extensions.Tests).

KBE authoring guidance (ci-failure-scan)

• Error Details is for readers. Paste the full exception, stack trace, or build error excerpt so the failure is understandable without opening the raw log.
• Build Analysis parses only the single JSON block under Error Message.
• ErrorMessage is a case-sensitive ordinal String.Contains substring copied verbatim from the failing log.
• Set BuildRetry to true only for a clear infrastructure retry case. ExcludeConsoleLog disables Helix console-log scanning.

Error Details

The test process dies with 0xC0000005 while the tiered-compilation background worker is re-jitting a method at tier 1; the fault is in PgoManager::getPgoInstrumentationResults. The foreground test thread is unrelated (file cleanup in FileCleanupTestBase.Dispose), and the crash has hit many unrelated test assemblies.

(1c90.145c): Access violation - code c0000005 (first/second chance not available)
coreclr!StressLog::InlinedStressLogOn [inlined in coreclr!WatsonLastChance+0x1f6]
coreclr!WatsonLastChance+0x1f6
coreclr!EEPolicy::LogFatalError+0x607
coreclr!EEPolicy::HandleFatalError+0x123
coreclr!CLRVectoredExceptionHandlerPhase3+0xb8bc5
coreclr!CLRVectoredExceptionHandler+0xb1
ntdll!KiUserExceptionDispatcher+0xf
coreclr!PgoManager::getPgoInstrumentationResults+0x87
coreclr!CEECodeGenInfo::getPgoInstrumentationResults+0x180
clrjit!Compiler::compInitOptions+0x38a
clrjit!Compiler::compCompileHelper+0x107
clrjit!jitNativeCode+0x1bb
clrjit!CILJit::compileMethod+0x9b
coreclr!UnsafeJitFunction+0x56a
coreclr!MethodDesc::JitCompileCodeLocked+0x8d
coreclr!MethodDesc::PrepareCode+0x17b
coreclr!TieredCompilationManager::CompileCodeVersion+0x85
coreclr!TieredCompilationManager::OptimizeMethod+0x1a
coreclr!TieredCompilationManager::DoBackgroundWork+0x48e
coreclr!TieredCompilationManager::BackgroundWorkerStart+0xde
['System.Private.Xml.Tests' END OF WORK ITEM LOG: Command exited with -1073741819]

Error Message

{
  "ErrorMessage": [
    "Access violation - code c0000005",
    "coreclr!PgoManager::getPgoInstrumentationResults"
  ],
  "ErrorPattern": "",
  "BuildRetry": false,
  "ExcludeConsoleLog": false
}

Agentic workflow metadata (ci-failure-scan)

Workflow artifact: ci-failure-scan
Artifact kind: kbe-verification
Verified match count: 2 hits in failure.log

Note

This issue was drafted with GitHub Copilot.

Known issue validation

Build: 🔎 https://dev.azure.com/dnceng-public/public/_build/results?buildId=1613037
Error message validated: [Access violation - code c0000005 coreclr!PgoManager::getPgoInstrumentationResults]
Result validation: ✅ Known issue matched with the provided build.
Validation performed at: 9/26/2026 2:23:51 AM UTC

Report

Build	Repository	Test	Pull Request
1613424	dotnet/runtime	Microsoft.Win32.Primitives.Tests.WorkItemExecution	#134676
1613197	dotnet/runtime	LibraryImportGenerator.Unit.Tests.WorkItemExecution	#132827
1613037	dotnet/runtime	System.Private.Xml.Tests.WorkItemExecution	#134676

Summary

24-Hour Hit Count	7-Day Hit Count	1-Month Count
3	3	3

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