[ci-scan] Build break: Crossgen2 OverflowException in LockFreeReaderHashtable on iossimulator

[github-actions]

Build Information

Build: https://dev.azure.com/dnceng-public/public/_build/results?buildId=1438268
Build error leg or test failing: iossimulator-arm64 Release AllSubsets_CoreCLR - System.Linq.Parallel.Tests

Error Details

Crossgen2 crashes with System.OverflowException in LockFreeReaderHashtable.Expand during R2R compilation of test assemblies on iossimulator-arm64. The workload eventually times out (exit 143 / SIGTERM). The overflow occurs in the GVM dependency analysis phase of crossgen2.

Microsoft.NET.CrossGen.targets(502,5): error : Error: Arithmetic operation resulted in an overflow.
System.OverflowException: Arithmetic operation resulted in an overflow.
   at Internal.TypeSystem.LockFreeReaderHashtable`2.Expand(TValue[] oldHashtable) in LockFreeReaderHashtable.cs:line 263
   at Internal.TypeSystem.LockFreeReaderHashtable`2.AddOrGetExistingInner(TValue value, Boolean& addedValue) in LockFreeReaderHashtable.cs:line 392
   at ILCompiler.DependencyAnalysis.GVMDependenciesNode.SearchDynamicDependencies(List`1 markedNodes, Int32 firstNode, NodeFactory factory) in GVMDependenciesNode.cs:line 80
   at ILCompiler.DependencyAnalysisFramework.DependencyAnalyzer`2.ProcessMarkStack() in DependencyAnalyzer.cs:line 287
   at ILCompiler.ReadyToRunCodegenCompilation.Compile(String outputFile) in ReadyToRunCodegenCompilation.cs:line 400
ERROR: WORKLOAD TIMED OUT - Killing user command..

Error Message

{
  "ErrorMessage": ["OverflowException: Arithmetic operation resulted in an overflow", "GVMDependenciesNode", "ReadyToRunCodegenCompilation"],
  "ErrorPattern": "",
  "BuildRetry": false,
  "ExcludeConsoleLog": false
}

Impact

• Pipeline: runtime-extra-platforms (def 154)
• Platform: iossimulator-arm64, CoreCLR Release
• Helix queue: iossimulator-arm64
• Exit code: 143 (SIGTERM from timeout)
• Occurrences: Persistent across the entire scanned window (builds 1425947 through 1438268, May 19–May 28); true origin may predate May 19.

First build it occurred

• Build: https://dev.azure.com/dnceng-public/public/_build/results?buildId=1425947
• Finished: 2026-05-19T09:03:10Z
• Computed within the scanned window; may not be the true origin.

Note

🔒 Integrity filter blocked 5 items

The following items were blocked because they don't meet the GitHub integrity level.

• #105444 search_issues: has lower integrity than agent requires. The agent cannot read data with integrity below "approved".
• #66079 search_issues: has lower integrity than agent requires. The agent cannot read data with integrity below "approved".
• #66787 search_issues: has lower integrity than agent requires. The agent cannot read data with integrity below "approved".
• #110173 search_issues: has lower integrity than agent requires. The agent cannot read data with integrity below "approved".
• #84911 search_issues: has lower integrity than agent requires. The agent cannot read data with integrity below "approved".

To allow these resources, lower min-integrity in your GitHub frontmatter:

tools:
  github:
    min-integrity: approved  # merged | approved | unapproved | none

Generated by CI Outer-Loop Failure Scanner · ● 29.7M · ◷

Report

Build	Repository	Test	Pull Request
1443972	dotnet/runtime	Interop/COM/ComWrappers/API/ComWrappersTestsBuiltInComDisabled/ComWrappersTestsBuiltInComDisabled.cmd	#127442
1441846	dotnet/runtime	System.Linq.Parallel.Tests.WorkItemExecution
1440990	dotnet/runtime	System.Linq.Parallel.Tests.WorkItemExecution	#128408
1441485	dotnet/runtime	Regression_PdbOnly_r_1.WorkItemExecution	#128423
1440694	dotnet/runtime	System.Linq.Parallel.Tests.WorkItemExecution	#127498
1439314	dotnet/runtime	System.Linq.Parallel.Tests.WorkItemExecution	#128705
1439078	dotnet/runtime	System.Linq.Parallel.Tests.WorkItemExecution	#125437

Summary

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

Known issue validation

Build: 🔎 https://dev.azure.com/dnceng-public/public/_build/results?buildId=1438268
Error message validated: [OverflowException: Arithmetic operation resulted in an overflow GVMDependenciesNode ReadyToRunCodegenCompilation]
Result validation: ✅ Known issue matched with the provided build.
Validation performed at: 6/2/2026 7:38:45 AM UTC

Report

Build	Repository	Test	Pull Request
1443972	dotnet/runtime	Interop/COM/ComWrappers/API/ComWrappersTestsBuiltInComDisabled/ComWrappersTestsBuiltInComDisabled.cmd	#127442
1441846	dotnet/runtime	System.Linq.Parallel.Tests.WorkItemExecution
1440990	dotnet/runtime	System.Linq.Parallel.Tests.WorkItemExecution	#128408
1441485	dotnet/runtime	Regression_PdbOnly_r_1.WorkItemExecution	#128423
1440694	dotnet/runtime	System.Linq.Parallel.Tests.WorkItemExecution	#127498
1439314	dotnet/runtime	System.Linq.Parallel.Tests.WorkItemExecution	#128705
1439078	dotnet/runtime	System.Linq.Parallel.Tests.WorkItemExecution	#125437
1438268	dotnet/runtime	System.Linq.Parallel.Tests.WorkItemExecution

Summary

24-Hour Hit Count	7-Day Hit Count	1-Month Count
0	8	8

Known issue validation

Build: 🔎 https://dev.azure.com/dnceng-public/public/_build/results?buildId=1438268
Error message validated: [OverflowException: Arithmetic operation resulted in an overflow GVMDependenciesNode ReadyToRunCodegenCompilation]
Result validation: ✅ Known issue matched with the provided build.
Validation performed at: 6/2/2026 7:38:45 AM UTC

[MichalStrehovsky]

@kotlarmilos this was using a very broad ErrorMessage and started marking things like https://helixr1107v0xd1eu3ibi6ka.blob.core.windows.net/dotnet-runtime-refs-pull-127442-merge-faeef2a09dc54789b9/Interop/1/console.9993e226.log?helixlogtype=result&skoid=8eda00af-b5ec-4be9-b69b-0919a2338892&sktid=72f988bf-86f1-41af-91ab-2d7cd011db47&skt=2026-06-02T07%3A36%3A49Z&ske=2026-06-02T08%3A36%3A49Z&sks=b&skv=2026-02-06&sv=2026-02-06&se=2026-06-02T08%3A36%3A49Z&sr=b&sp=rl&sig=MhysKiinYuSsXwKvBDZ3OQnOVVFWKnaM7w3WRtvBsJM%3D as this known issue (the test run prints this as part of normal execution, it's not the thing that failed in the log, but Build Analysis marked this as known).

The failing test is actually later in the log:

Expected: 100
Actual: -532462766
END EXECUTION - FAILED

I've updated the ErrorMessage to be less broad ["OverflowException: Arithmetic operation resulted in an overflow", "GVMDependenciesNode", "ReadyToRunCodegenCompilation"],

[MichalStrehovsky]

cc @BrzVlad this is from the GVM analysis in crossgen. This might be some kind of generic recursion/expansion that expands like crazy (I know this failure mode; if we didn't run out of integers, we'd run out of memory).

[BrzVlad]

Thanks, will take a look at it