[ci-scan] Test failure: Async2ManagedThreadId.TestThreadIdReflectsResumptionThread Assert.Equal under JIT stress

[github-actions]

Build Information

Build: https://dev.azure.com/dnceng-public/public/_build/results?buildId=1492736
Build error leg or test failing: coreclr Pri1 Runtime Tests Run linux x64 checked - _regression_managed_thread_id::Async2ManagedThreadId.TestThreadIdReflectsResumptionThread

Pipeline: runtime-coreclr jitstress (definition 109, optional rolling stress pipeline), branch main. The failure reproduces across multiple stress-mode legs and persists into follow-up build 1494001.

Error Details

Under JIT stress, Async2ManagedThreadId.TestThreadIdReflectsResumptionThread fails its Assert.Equal check: the managed thread id observed after the async resumption does not match the expected value (the concrete expected/actual thread-id numbers vary from run to run, so they are excluded from the match signature):

Running test: _regression_managed_thread_id::Async2ManagedThreadId.TestThreadIdReflectsResumptionThread()
Xunit.Sdk.EqualException: Assert.Equal() Failure: Values differ
Expected: 1
Actual:   11
   at Xunit.Assert.Equal[T](T expected, T actual, IEqualityComparer`1 comparer)
   at Async2ManagedThreadId.TestThreadIdReflectsResumptionThreadAsync()
Failed test: _regression_managed_thread_id::Async2ManagedThreadId.TestThreadIdReflectsResumptionThread()

Error Message

{
  "ErrorMessage": [
    "Assert.Equal() Failure: Values differ",
    "at Async2ManagedThreadId.TestThreadIdReflectsResumptionThreadAsync()"
  ],
  "ErrorPattern": "",
  "BuildRetry": false,
  "ExcludeConsoleLog": false
}

First build it occurred

Present in source build 1492736 and confirmed still failing across multiple legs of follow-up build 1494001. The signature is scoped to the async-resumption stack frame, which appears only on failure.

Duplicate search

Searched open and closed Known Build Error issues for Async2ManagedThreadId, TestThreadIdReflectsResumptionThread, and the assertion text: no existing KBE.

---

_{Filed by the CI outer-loop failure scanner (detection only). Mitigation — a fix PR or JIT-owner hand-off — is handled by the companion ci-failure-fix workflow, which walks open [ci-scan] KBEs.}

Note

This issue was generated with the assistance of GitHub Copilot (AI). Signatures and build references were verified against public AzDO / Helix logs.

Note

🔒 Integrity filter blocked 5 items

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

• #114222 search_issues: has lower integrity than agent requires. The agent cannot read data with integrity below "approved".
• #127541 search_issues: has lower integrity than agent requires. The agent cannot read data with integrity below "approved".
• #117370 search_issues: has lower integrity than agent requires. The agent cannot read data with integrity below "approved".
• #50848 search_issues: has lower integrity than agent requires. The agent cannot read data with integrity below "approved".
• #19341 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:

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

Generated by CI Outer-Loop Failure Scanner · ● 12.9M · ◷

Report

Build	Repository	Test	Pull Request
1498487	dotnet/runtime	_regression_managed_thread_id::Async2ManagedThreadId.TestThreadIdReflectsResumptionThread()
1496394	dotnet/runtime	_regression_managed_thread_id::Async2ManagedThreadId.TestThreadIdReflectsResumptionThread()
1496001	dotnet/runtime	_regression_managed_thread_id::Async2ManagedThreadId.TestThreadIdReflectsResumptionThread()	#130255
1494962	dotnet/runtime	_regression_managed_thread_id::Async2ManagedThreadId.TestThreadIdReflectsResumptionThread()
1494861	dotnet/runtime	_regression_managed_thread_id::Async2ManagedThreadId.TestThreadIdReflectsResumptionThread()
1494677	dotnet/runtime	_regression_managed_thread_id::Async2ManagedThreadId.TestThreadIdReflectsResumptionThread()
1494597	dotnet/runtime	_regression_managed_thread_id::Async2ManagedThreadId.TestThreadIdReflectsResumptionThread()
1494572	dotnet/runtime	_regression_managed_thread_id::Async2ManagedThreadId.TestThreadIdReflectsResumptionThread()
1494353	dotnet/runtime	_regression_managed_thread_id::Async2ManagedThreadId.TestThreadIdReflectsResumptionThread()
1494320	dotnet/runtime	_regression_managed_thread_id::Async2ManagedThreadId.TestThreadIdReflectsResumptionThread()
1494227	dotnet/runtime	_regression_managed_thread_id::Async2ManagedThreadId.TestThreadIdReflectsResumptionThread()

Summary

24-Hour Hit Count	7-Day Hit Count	1-Month Count
1	11	11

[VincentBu]

Failed in: runtime-coreclr jitstress-isas-x86 20260704.1

Failed tests:

coreclr linux x64 Checked jitstress_isas_1_x86_noavx2 @ AzureLinux.3.Amd64.Open
- _regression_managed_thread_id::Async2ManagedThreadId.TestThreadIdReflectsResumptionThread()
coreclr linux x64 Checked jitstress_isas_1_x86_noavx512_vectort128 @ AzureLinux.3.Amd64.Open
- _regression_managed_thread_id::Async2ManagedThreadId.TestThreadIdReflectsResumptionThread()
coreclr linux x64 Checked jitstress_isas_2_x86_vectort512 @ AzureLinux.3.Amd64.Open
- _regression_managed_thread_id::Async2ManagedThreadId.TestThreadIdReflectsResumptionThread()
coreclr linux x64 Checked jitstress_isas_2_x86_noavx @ AzureLinux.3.Amd64.Open
- _regression_managed_thread_id::Async2ManagedThreadId.TestThreadIdReflectsResumptionThread()
coreclr linux x64 Checked jitstress_isas_1_x86_noavx @ AzureLinux.3.Amd64.Open
- _regression_managed_thread_id::Async2ManagedThreadId.TestThreadIdReflectsResumptionThread()
coreclr linux x64 Checked jitstress_isas_2_x86_noavx512 @ AzureLinux.3.Amd64.Open
- _regression_managed_thread_id::Async2ManagedThreadId.TestThreadIdReflectsResumptionThread()
coreclr linux x64 Checked jitstress_isas_2_x86_evex @ AzureLinux.3.Amd64.Open
- _regression_managed_thread_id::Async2ManagedThreadId.TestThreadIdReflectsResumptionThread()
coreclr linux x64 Checked jitstress_isas_2_x86_vectort128 @ AzureLinux.3.Amd64.Open
- _regression_managed_thread_id::Async2ManagedThreadId.TestThreadIdReflectsResumptionThread()
coreclr linux x64 Checked jitstress_isas_1_x86_vectort128 @ AzureLinux.3.Amd64.Open
- _regression_managed_thread_id::Async2ManagedThreadId.TestThreadIdReflectsResumptionThread()
coreclr linux x64 Checked jitstress_isas_1_x86_vectort512 @ AzureLinux.3.Amd64.Open
- _regression_managed_thread_id::Async2ManagedThreadId.TestThreadIdReflectsResumptionThread()
coreclr linux x64 Checked jitstress_isas_2_x86_noavx2 @ AzureLinux.3.Amd64.Open
- _regression_managed_thread_id::Async2ManagedThreadId.TestThreadIdReflectsResumptionThread()
coreclr linux x64 Checked jitstress_isas_1_x86_evex @ AzureLinux.3.Amd64.Open
- _regression_managed_thread_id::Async2ManagedThreadId.TestThreadIdReflectsResumptionThread()
coreclr linux x64 Checked jitstress_isas_1_x86_noavx512 @ AzureLinux.3.Amd64.Open
- _regression_managed_thread_id::Async2ManagedThreadId.TestThreadIdReflectsResumptionThread()
coreclr linux x64 Checked jitstress_isas_2_x86_noavx512_vectort128 @ AzureLinux.3.Amd64.Open
- _regression_managed_thread_id::Async2ManagedThreadId.TestThreadIdReflectsResumptionThread()
coreclr windows x86 Checked jitstress_isas_1_x86_noavx512 @ Windows.10.Amd64.Open
- _regression_managed_thread_id::Async2ManagedThreadId.TestThreadIdReflectsResumptionThread()
coreclr windows x86 Checked jitstress_isas_1_x86_evex @ Windows.10.Amd64.Open
- _regression_managed_thread_id::Async2ManagedThreadId.TestThreadIdReflectsResumptionThread()
coreclr windows x86 Checked jitstress_isas_2_x86_noavx2 @ Windows.10.Amd64.Open
- _regression_managed_thread_id::Async2ManagedThreadId.TestThreadIdReflectsResumptionThread()
coreclr windows x86 Checked jitstress_isas_1_x86_noavx @ Windows.10.Amd64.Open
- _regression_managed_thread_id::Async2ManagedThreadId.TestThreadIdReflectsResumptionThread()
coreclr windows x86 Checked jitstress_isas_2_x86_noavx512 @ Windows.10.Amd64.Open
- _regression_managed_thread_id::Async2ManagedThreadId.TestThreadIdReflectsResumptionThread()
coreclr windows x86 Checked jitstress_isas_1_x86_noavx2 @ Windows.10.Amd64.Open
- _regression_managed_thread_id::Async2ManagedThreadId.TestThreadIdReflectsResumptionThread()
coreclr windows x86 Checked jitstress_isas_1_x86_vectort128 @ Windows.10.Amd64.Open
- _regression_managed_thread_id::Async2ManagedThreadId.TestThreadIdReflectsResumptionThread()
coreclr windows x86 Checked jitstress_isas_1_x86_vectort512 @ Windows.10.Amd64.Open
- _regression_managed_thread_id::Async2ManagedThreadId.TestThreadIdReflectsResumptionThread()
coreclr windows x86 Checked jitstress_isas_1_x86_noavx512_vectort128 @ Windows.10.Amd64.Open
- _regression_managed_thread_id::Async2ManagedThreadId.TestThreadIdReflectsResumptionThread()
coreclr windows x86 Checked jitstress_isas_2_x86_noavx @ Windows.10.Amd64.Open
- _regression_managed_thread_id::Async2ManagedThreadId.TestThreadIdReflectsResumptionThread()
coreclr windows x86 Checked jitstress_isas_2_x86_evex @ Windows.10.Amd64.Open
- _regression_managed_thread_id::Async2ManagedThreadId.TestThreadIdReflectsResumptionThread()
coreclr windows x86 Checked jitstress_isas_2_x86_vectort128 @ Windows.10.Amd64.Open
- _regression_managed_thread_id::Async2ManagedThreadId.TestThreadIdReflectsResumptionThread()
coreclr windows x86 Checked jitstress_isas_2_x86_vectort512 @ Windows.10.Amd64.Open
- _regression_managed_thread_id::Async2ManagedThreadId.TestThreadIdReflectsResumptionThread()
coreclr windows x86 Checked jitstress_isas_2_x86_noavx512_vectort128 @ Windows.10.Amd64.Open
- _regression_managed_thread_id::Async2ManagedThreadId.TestThreadIdReflectsResumptionThread()
coreclr windows x64 Checked jitstress_isas_1_x86_noavx @ Windows.10.Amd64.Open
- _regression_managed_thread_id::Async2ManagedThreadId.TestThreadIdReflectsResumptionThread()
coreclr windows x64 Checked jitstress_isas_1_x86_noavx512 @ Windows.10.Amd64.Open
- _regression_managed_thread_id::Async2ManagedThreadId.TestThreadIdReflectsResumptionThread()
coreclr windows x64 Checked jitstress_isas_1_x86_noavx512_vectort128 @ Windows.10.Amd64.Open
- _regression_managed_thread_id::Async2ManagedThreadId.TestThreadIdReflectsResumptionThread()
coreclr windows x64 Checked jitstress_isas_1_x86_vectort128 @ Windows.10.Amd64.Open
- _regression_managed_thread_id::Async2ManagedThreadId.TestThreadIdReflectsResumptionThread()
coreclr windows x64 Checked jitstress_isas_1_x86_evex @ Windows.10.Amd64.Open
- _regression_managed_thread_id::Async2ManagedThreadId.TestThreadIdReflectsResumptionThread()
coreclr windows x64 Checked jitstress_isas_1_x86_noavx2 @ Windows.10.Amd64.Open
- _regression_managed_thread_id::Async2ManagedThreadId.TestThreadIdReflectsResumptionThread()
coreclr windows x64 Checked jitstress_isas_2_x86_evex @ Windows.10.Amd64.Open
- _regression_managed_thread_id::Async2ManagedThreadId.TestThreadIdReflectsResumptionThread()
coreclr windows x64 Checked jitstress_isas_2_x86_noavx @ Windows.10.Amd64.Open
- _regression_managed_thread_id::Async2ManagedThreadId.TestThreadIdReflectsResumptionThread()
coreclr windows x64 Checked jitstress_isas_1_x86_vectort512 @ Windows.10.Amd64.Open
- _regression_managed_thread_id::Async2ManagedThreadId.TestThreadIdReflectsResumptionThread()
coreclr windows x64 Checked jitstress_isas_2_x86_noavx2 @ Windows.10.Amd64.Open
- _regression_managed_thread_id::Async2ManagedThreadId.TestThreadIdReflectsResumptionThread()
coreclr windows x64 Checked jitstress_isas_2_x86_noavx512 @ Windows.10.Amd64.Open
- _regression_managed_thread_id::Async2ManagedThreadId.TestThreadIdReflectsResumptionThread()
coreclr windows x64 Checked jitstress_isas_2_x86_vectort512 @ Windows.10.Amd64.Open
- _regression_managed_thread_id::Async2ManagedThreadId.TestThreadIdReflectsResumptionThread()
coreclr windows x64 Checked jitstress_isas_2_x86_vectort128 @ Windows.10.Amd64.Open
- _regression_managed_thread_id::Async2ManagedThreadId.TestThreadIdReflectsResumptionThread()
coreclr windows x64 Checked jitstress_isas_2_x86_noavx512_vectort128 @ Windows.10.Amd64.Open
- _regression_managed_thread_id::Async2ManagedThreadId.TestThreadIdReflectsResumptionThread()
coreclr osx x64 Checked jitstress_isas_1_x86_vectort128 @ OSX.15.Amd64.Open
- _regression_managed_thread_id::Async2ManagedThreadId.TestThreadIdReflectsResumptionThread()
coreclr osx x64 Checked jitstress_isas_2_x86_noavx512_vectort128 @ OSX.15.Amd64.Open
- _regression_managed_thread_id::Async2ManagedThreadId.TestThreadIdReflectsResumptionThread()
coreclr osx x64 Checked jitstress_isas_2_x86_noavx2 @ OSX.15.Amd64.Open
- _regression_managed_thread_id::Async2ManagedThreadId.TestThreadIdReflectsResumptionThread()
coreclr osx x64 Checked jitstress_isas_2_x86_vectort512 @ OSX.15.Amd64.Open
- _regression_managed_thread_id::Async2ManagedThreadId.TestThreadIdReflectsResumptionThread()
coreclr osx x64 Checked jitstress_isas_2_x86_vectort128 @ OSX.15.Amd64.Open
- _regression_managed_thread_id::Async2ManagedThreadId.TestThreadIdReflectsResumptionThread()
coreclr osx x64 Checked jitstress_isas_2_x86_evex @ OSX.15.Amd64.Open
- _regression_managed_thread_id::Async2ManagedThreadId.TestThreadIdReflectsResumptionThread()
coreclr osx x64 Checked jitstress_isas_2_x86_noavx @ OSX.15.Amd64.Open
- _regression_managed_thread_id::Async2ManagedThreadId.TestThreadIdReflectsResumptionThread()
coreclr osx x64 Checked jitstress_isas_1_x86_noavx512_vectort128 @ OSX.15.Amd64.Open
- _regression_managed_thread_id::Async2ManagedThreadId.TestThreadIdReflectsResumptionThread()
coreclr osx x64 Checked jitstress_isas_1_x86_noavx @ OSX.15.Amd64.Open
- _regression_managed_thread_id::Async2ManagedThreadId.TestThreadIdReflectsResumptionThread()
coreclr osx x64 Checked jitstress_isas_2_x86_noavx512 @ OSX.15.Amd64.Open
- _regression_managed_thread_id::Async2ManagedThreadId.TestThreadIdReflectsResumptionThread()
coreclr osx x64 Checked jitstress_isas_1_x86_evex @ OSX.15.Amd64.Open
- _regression_managed_thread_id::Async2ManagedThreadId.TestThreadIdReflectsResumptionThread()
coreclr osx x64 Checked jitstress_isas_1_x86_noavx512 @ OSX.15.Amd64.Open
- _regression_managed_thread_id::Async2ManagedThreadId.TestThreadIdReflectsResumptionThread()
coreclr osx x64 Checked jitstress_isas_1_x86_noavx2 @ OSX.15.Amd64.Open
- _regression_managed_thread_id::Async2ManagedThreadId.TestThreadIdReflectsResumptionThread()
coreclr osx x64 Checked jitstress_isas_1_x86_vectort512 @ OSX.15.Amd64.Open
- _regression_managed_thread_id::Async2ManagedThreadId.TestThreadIdReflectsResumptionThread()

Error message:

Assert.Equal() Failure: Values differ
Expected: 1
Actual:   7

Stack trace:

   at Xunit.Assert.Equal[T](T expected, T actual, IEqualityComparer`1 comparer) in /_/src/arcade/src/Microsoft.DotNet.XUnitAssert/src/EqualityAsserts.cs:line 102
   at Async2ManagedThreadId.TestThreadIdReflectsResumptionThreadAsync()
   at Program.<<Main>$>g__TestExecutor49|0_50(StreamWriter tempLogSw, StreamWriter statsCsvSw, <>c__DisplayClass0_0&)

[github-actions]

Workflow artifact: ci-fix
Artifact kind: handoff
Linked KBE: #130212

Root-cause analysis (read-only hand-off)

Under runtime-coreclr jitstress (AzDO definition 109) _regression_managed_thread_id::Async2ManagedThreadId.TestThreadIdReflectsResumptionThread fails its assertion:

Xunit.Sdk.EqualException: Assert.Equal() Failure: Values differ
Expected: 1
Actual:   11
  at Async2ManagedThreadId.TestThreadIdReflectsResumptionThreadAsync()

The test verifies that after an async resumption Environment.CurrentManagedThreadId reflects the thread the continuation actually resumed on. Under JIT stress the observed id does not match the expected one (the concrete numbers vary run-to-run and across the many jitstress_isas_* legs, per the failure aggregation on this issue). A managed-thread-id that is correct under the default JIT but wrong under JIT stress points at a runtime-async / JIT stress codegen issue in continuation resumption, not at a test defect.

Per this workflow's rules JIT codegen fixes and codegen-stress workarounds are out of bounds for an automated PR, so this is a hand-off.

Evidence

• Failing build: 1492736, still failing across many legs of follow-up 1494001 and 1494212 (broad jitstress_isas_* fan-out on linux/windows/osx).
• Affected pipeline: runtime-coreclr jitstress (def 109) and the jitstress-isas-x86 variants.

Suggested reviewers / area contacts

• area-CodeGen-coreclr (JIT stress / runtime-async resumption): @JulieLeeMSFT, @dotnet/jit-contrib

Note

This root-cause hand-off was generated by an AI/Copilot agent (ci-failure-fix). No code change was produced because the evidence points to JIT-stress / runtime-async codegen that must not be worked around in test code. Please verify before acting.

Note

🔒 Integrity filter blocked 6 items

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

• #128501 search_issues: has lower integrity than agent requires. The agent cannot read data with integrity below "approved".
• #104998 search_issues: has lower integrity than agent requires. The agent cannot read data with integrity below "approved".
• #104750 search_issues: has lower integrity than agent requires. The agent cannot read data with integrity below "approved".
• #97491 search_issues: has lower integrity than agent requires. The agent cannot read data with integrity below "approved".
• [ci-scan] Test failure: AsyncProfilerTests.StateMachineAsync_CallstackStressWithVaryingDepths under libraries-jitstress #129938 issue_read: has lower integrity than agent requires. The agent cannot read data with integrity below "approved".
• [ci-scan] Test failure: System.Threading.Tests.MutexTests.CrossProcess_NamedMutex_ConcurrentCreateOrOpen #130125 issue_read: 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 Fixer · ● 9.2M · ◷

[dotnet-policy-service]

Tagging subscribers to this area: @JulieLeeMSFT, @jakobbotsch
See info in area-owners.md if you want to be subscribed.

[JulieLeeMSFT]

cc @jakobbotsch, @VSadov.