System.Threading.Threads.Tests.ThreadTests.IsBackgroundTest test failure

[jkotas]

    System.Threading.Threads.Tests.ThreadTests.IsBackgroundTest [FAIL]
      Assert.Throws() Failure: No exception was thrown
      Expected: typeof(System.Threading.ThreadStateException)
      Stack Trace:
        /_/src/libraries/System.Threading.Thread/tests/ThreadTests.cs(580,0): at System.Threading.Threads.Tests.ThreadTests.IsBackgroundTest()
        /_/src/coreclr/System.Private.CoreLib/src/System/Reflection/MethodBaseInvoker.CoreCLR.cs(36,0): at System.Reflection.MethodBaseInvoker.InterpretedInvoke_Method(Object obj, IntPtr* args)
        /_/src/libraries/System.Private.CoreLib/src/System/Reflection/MethodBaseInvoker.cs(57,0): at System.Reflection.MethodBaseInvoker.InvokeWithNoArgs(Object obj, BindingFlags invokeAttr)

Build Information

Build: https://dev.azure.com/dnceng-public/cbb18261-c48f-4abb-8651-8cdcb5474649/_build/results?buildId=1230390
Build error leg or test failing: System.Threading.Threads.Tests.ThreadTests.IsBackgroundTest
Pull request: #122513

Error Message

Fill the error message using step by step known issues guidance.

{
  "ErrorMessage": "System.Threading.Threads.Tests.ThreadTests.IsBackgroundTest [FAIL]",
  "ErrorPattern": "",
  "BuildRetry": false,
  "ExcludeConsoleLog": false
}

Known issue validation

Build: 🔎 https://dev.azure.com/dnceng-public/public/_build/results?buildId=1230390
Error message validated: [System.Threading.Threads.Tests.ThreadTests.IsBackgroundTest [FAIL]]
Result validation: ✅ Known issue matched with the provided build.
Validation performed at: 12/13/2025 9:22:29 AM UTC

Report

Build	Definition	Test	Pull Request
1230743	dotnet/runtime	System.Threading.Threads.Tests.ThreadTests.IsBackgroundTest	#122510
1230390	dotnet/runtime	System.Threading.Threads.Tests.ThreadTests.IsBackgroundTest	#122513

Summary

24-Hour Hit Count	7-Day Hit Count	1-Month Count
0	2	2

[dotnet-policy-service]

Tagging subscribers to this area: @mangod9
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[jkotas]

@jkoritzinsky Potential regression from the wait system unification PR. Do we need an equivalent of this change https://github.com/dotnet/runtime/pull/117788/files#diff-c9b599d1c402a4d140cd0d88101b8f167209e6f495c66ac294d04b1227199e38R397-R405 in NAOT?

[jkoritzinsky]

This is a regression from the wait subsystem unification PR. Looks like the failures are in CoreCLR tests. I have an idea of the fix, should be able to get to it early next week.

[SakeTao]

Failed in: runtime-coreclr libraries-jitstress2-jitstressregs 20251213.1

Failed tests:

net11.0-linux-Release-x64-jitstress2_jitstressregs0x80-AzureLinux.3.Amd64.Open
    - System.Threading.Threads.Tests.ThreadTests.IsBackgroundTest

Error message:

Assert.Throws() Failure: No exception was thrown
Expected: typeof(System.Threading.ThreadStateException)

Stack trace:

   at System.Threading.Threads.Tests.ThreadTests.IsBackgroundTest() in /_/src/libraries/System.Threading.Thread/tests/ThreadTests.cs:line 580
   at System.Reflection.MethodBaseInvoker.InterpretedInvoke_Method(Object obj, IntPtr* args) in /_/src/coreclr/System.Private.CoreLib/src/System/Reflection/MethodBaseInvoker.CoreCLR.cs:line 36
   at System.Reflection.MethodBaseInvoker.InvokeWithNoArgs(Object obj, BindingFlags invokeAttr) in /_/src/libraries/System.Private.CoreLib/src/System/Reflection/MethodBaseInvoker.cs:line 57