[ci-scan] Test failure: SOS.Tests.ObjectGcHelperTests.DumpAlc_ResolvesDefaultLoadContext

[lewing]

Build Information

Build: https://dev.azure.com/dnceng-public/public/_build/results?buildId=1620300
Build error leg or test failing: runtime-diagnostics SOSTests (all platforms) - SOS.Tests.ObjectGcHelperTests.DumpAlc_ResolvesDefaultLoadContext
Pull request: #135054

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

Every runtime-diagnostics PR run queued since about 2026-10-01 20:00 UTC fails DumpAlc_ResolvesDefaultLoadContext on all SOSTests legs (linux-x64, linux-arm64, windows-x64, windows-x86, osx-x64), for every debugger host (dotnet-dump, lldb, cdb). dumpalc cannot resolve the managed AssemblyLoadContext. Seen on #134813, #135054, #135055, #133890, #135059, #134966, #135044. The #132584 run queued at 17:09 UTC passed.

The pipeline checks out dotnet/diagnostics main, so the regression may come from either repo. Changes in the window include #134875 (internal metadata interfaces; touched vm/assembly*; runtime-diagnostics did not run on it) and dotnet/diagnostics#6080 / dotnet/diagnostics#6075. Not yet confirmed which one is responsible.

failed SOS.Tests.ObjectGcHelperTests.DumpAlc_ResolvesDefaultLoadContext(config: scenarios/Cdb/Core/net11/Dump/Workstation/Heap) (3s 347ms)
  Xunit.Runner.InProc.SystemConsole.TestingPlatform.XunitException: SOS.TestHarness.SosAssertException : SOS assertion failed.
    host:     cdb
    command:  dumpalc 55671b8
    expected: output to contain "DefaultAssemblyLoadContext"
  --- actual output ---
  Failed to get the AssemblyLoadContext
  ---------------------
    at SOS.TestHarness.SosOutput.AssertContains(String literal) in /_/src/tests/SOS.TestHarness/SosOutput.cs:321

Error Message

{
  "ErrorMessage": "failed SOS.Tests.ObjectGcHelperTests.DumpAlc_ResolvesDefaultLoadContext",
  "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=1620300
Error message validated: [failed SOS.Tests.ObjectGcHelperTests.DumpAlc_ResolvesDefaultLoadContext]
Result validation: ✅ Known issue matched with the provided build.
Validation performed at: 10/2/2026 12:36:04 AM UTC

Report

Build	Repository	Test	Pull Request
1621202	dotnet/runtime	SOS_osx-arm64_Release-Net11.WorkItemExecution	#135100
1621016	dotnet/runtime	SOS_osx-arm64_Release-Net11.WorkItemExecution	#135010
1621045	dotnet/runtime	SOS_linux-x64_Release-Net11.WorkItemExecution	#135093
1620762	dotnet/runtime	SOS_osx-arm64_Release-Net11.WorkItemExecution	#134819
1620702	dotnet/runtime	SOS_osx-x64_Release-Net11.WorkItemExecution
1620618	dotnet/runtime	SOS_osx-x64_Release-Net11.WorkItemExecution	#134813
1620490	dotnet/runtime	SOS_osx-x64_Release-Net11.WorkItemExecution	#132584
1620383	dotnet/runtime	SOS_osx-x64_Release-Net11.WorkItemExecution	#135059
1620459	dotnet/runtime	SOS_osx-x64_Release-Net11.WorkItemExecution	#135068
1620433	dotnet/runtime	SOS_osx-x64_Release-Net11.WorkItemExecution	#135044
1620397	dotnet/runtime	SOS_osx-arm64_Release-Net11.WorkItemExecution	#134966
1620349	dotnet/runtime	SOS_osx-x64_Release-Net11.WorkItemExecution	#133890
1620305	dotnet/runtime	SOS_osx-x64_Release-Net11.WorkItemExecution	#135055
1620300	dotnet/runtime	SOS_osx-x64_Release-Net11.WorkItemExecution	#135054

Summary

24-Hour Hit Count	7-Day Hit Count	1-Month Count
14	14	14

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