Test failure: System.Threading.ThreadPools.Tests.ThreadPoolTests.FileStreamFlushAsyncThreadPoolDeadlockTest

**Failed in:** [runtime-coreclr libraries-jitstress 20260506.1](https://dev.azure.com/dnceng-public/cbb18261-c48f-4abb-8651-8cdcb5474649/_build/results?buildId=1410064)

**Failed tests:**
```
net11.0-linux-Release-x64-no_tiered_compilation-AzureLinux.3.Amd64.Open
- System.Threading.ThreadPools.Tests.ThreadPoolTests.FileStreamFlushAsyncThreadPoolDeadlockTest

```

**Error message:**
```
Microsoft.DotNet.RemoteExecutor.RemoteExecutionException : Half-way through waiting for remote process.
Timed out at 5/6/2026 7:59:07 AM after 60000ms waiting for remote process.
Process ID: 3372
Handle: 127015638209024
Name: dotnet
MainModule: /datadisks/disk1/work/B0CD08E4/p/dotnet
StartTime: 5/6/2026 7:58:07 AM
TotalProcessorTime: 00:00:01.4300000

```

**Stack trace:**
```
at Microsoft.DotNet.RemoteExecutor.RemoteInvokeHandle.Dispose(Boolean disposing) in /_/src/arcade/src/Microsoft.DotNet.RemoteExecutor/src/RemoteInvokeHandle.cs:line 225
at System.Reflection.MethodBaseInvoker.InterpretedInvoke_Method(Object obj, IntPtr* args) in /_/src/coreclr/System.Private.CoreLib/src/System/Reflection/MethodBaseInvoker.CoreCLR.cs:line 37
at System.Reflection.MethodBaseInvoker.InvokeWithNoArgs(Object obj, BindingFlags invokeAttr) in /_/src/libraries/System.Private.CoreLib/src/System/Reflection/MethodBaseInvoker.cs:line 57
```

### Known Issue Error Message

**DO NOT USE JSON BELOW IF THIS IS A BUILD BREAK** otherwise build analysis will allow pull requests to merge that break the build worse. For a build break, do not use this issue form. Make a regular new issue.

Fill the error message using [step by step known issues guidance](https://github.com/dotnet/arcade/blob/main/Documentation/Build%20Analysis/KnownIssueJsonStepByStep.md).

```json
{
"ErrorMessage": ["ThreadPoolTests.FileStreamFlushAsyncThreadPoolDeadlockTest [FAIL]","Timed out"],
"ErrorPattern": "",
"BuildRetry": false,
"ExcludeConsoleLog": false
}
```

### Known issue validation
**Build: :mag_right:**
**Result validation:** :warning: Validation could not be done without an Azure DevOps build URL on the issue. Please add it to the "**Build:** :mag_right:" line.
**Validation performed at:** 8/4/2026 10:30:57 PM UTC

### Report

|Build|Repository|Test|Pull Request|
|---|---|---|---|
|[1574183](https://dev.azure.com/dnceng-public/public/_build/results?buildId=1574183)|dotnet/runtime|[System.Threading.ThreadPools.Tests.ThreadPoolTests.FileStreamFlushAsyncThreadPoolDeadlockTest](https://dev.azure.com/dnceng-public/public/_build/results?buildId=1574183&view=ms.vss-test-web.build-test-results-tab&runId=43379356&resultId=181133)|dotnet/runtime#132419|
#### Summary
|24-Hour Hit Count|7-Day Hit Count|1-Month Count|
|---|---|---|
|0|0|1|