ServiceHub.RoslynCodeAnalysisService.exe or devenv.exe could consume a CPU core permanently

Version Used: Since VS 17.4 preview 3 Steps to Reproduce:

It is hard to reproduce it with a describable procedure.

I posted this issue initially on VS feedback, but no reply were heard for days. It occurred quite a few times a day on my computer.

When this issue occurs, ServiceHub.RoslynCodeAnalysisService.exe or sometimes devenv.exe, will consume all resource of a CPU core and its usage ratio won’t subside.

I used Process Explorer to find out that the problematic thread has the following stack in ServiceHub.RoslynCodeAnalysisService.exe, when its CPU consumption rate was high:

System.Core.dll!System.Collections.Generic.HashSet`1.Contains+0xbe
Microsoft.CodeAnalysis.dll!Microsoft.CodeAnalysis.Diagnostics.AnalyzerExecutor.ShouldExecuteNode+0x23
Microsoft.CodeAnalysis.dll!Microsoft.CodeAnalysis.Diagnostics.AnalyzerExecutor.ExecuteSyntaxNodeActions+0xfd
Microsoft.CodeAnalysis.dll!Microsoft.CodeAnalysis.Diagnostics.AnalyzerExecutor.ExecuteSyntaxNodeActionsCore+0x1f6
Microsoft.CodeAnalysis.dll!Microsoft.CodeAnalysis.Diagnostics.AnalyzerExecutor.TryExecuteSyntaxNodeActions+0xda
Microsoft.CodeAnalysis.dll!<>c__DisplayClass12_0.<TryExecuteDeclaringReferenceActions>g__executeNodeActionsByKind|2+0x232
Microsoft.CodeAnalysis.dll!<>c__DisplayClass12_0.<TryExecuteDeclaringReferenceActions>g__executeNodeActions|1+0x2a
Microsoft.CodeAnalysis.dll!Microsoft.CodeAnalysis.Diagnostics.AnalyzerDriver`1.TryExecuteDeclaringReferenceActions+0x2c9
Microsoft.CodeAnalysis.dll!Microsoft.CodeAnalysis.Diagnostics.AnalyzerDriver`1.TryExecuteDeclaringReferenceActions+0x420
Microsoft.CodeAnalysis.dll!<TryProcessSymbolDeclaredAsync>d__133.MoveNext+0x40c
mscorlib.dll!System.Runtime.CompilerServices.AsyncTaskMethodBuilder`1.Start+0x7a
Microsoft.CodeAnalysis.dll!Microsoft.CodeAnalysis.Diagnostics.AnalyzerDriver.TryProcessSymbolDeclaredAsync+0x8b
Microsoft.CodeAnalysis.dll!<TryProcessEventCoreAsync>d__132.MoveNext+0x1e4
mscorlib.dll!System.Runtime.CompilerServices.AsyncTaskMethodBuilder`1.Start+0x7a
Microsoft.CodeAnalysis.dll!Microsoft.CodeAnalysis.Diagnostics.AnalyzerDriver.TryProcessEventCoreAsync+0x8b
Microsoft.CodeAnalysis.dll!<ProcessEventAsync>d__130.MoveNext+0x8f
mscorlib.dll!System.Runtime.CompilerServices.AsyncTaskMethodBuilder.Start+0x80
Microsoft.CodeAnalysis.dll!Microsoft.CodeAnalysis.Diagnostics.AnalyzerDriver.ProcessEventAsync+0x70
Microsoft.CodeAnalysis.dll!<ProcessCompilationEventsCoreAsync>d__129.MoveNext+0x456
mscorlib.dll!System.Runtime.CompilerServices.AsyncTaskMethodBuilder`1.Start+0x7a
Microsoft.CodeAnalysis.dll!Microsoft.CodeAnalysis.Diagnostics.AnalyzerDriver.ProcessCompilationEventsCoreAsync+0x7d
Microsoft.CodeAnalysis.dll!<<ProcessCompilationEventsAsync>b__2>d.MoveNext+0x61
mscorlib.dll!System.Runtime.CompilerServices.AsyncTaskMethodBuilder`1.Start+0x7a
Microsoft.CodeAnalysis.dll!<>c__DisplayClass128_0.<ProcessCompilationEventsAsync>b__2+0x59
mscorlib.dll!System.Threading.Tasks.Task`1.InnerInvoke+0x4e
mscorlib.dll!System.Threading.Tasks.Task.Execute+0x47
mscorlib.dll!System.Threading.ExecutionContext.RunInternal+0x172
mscorlib.dll!System.Threading.ExecutionContext.Run+0x15
mscorlib.dll!System.Threading.Tasks.Task.ExecuteWithThreadLocal+0x231
mscorlib.dll!System.Threading.Tasks.Task.ExecuteEntry+0xa1
mscorlib.dll!System.Threading.ThreadPoolWorkQueue.Dispatch+0x156
[Unmanaged to Managed Transition]
clr.dll!LogHelp_LogAssert+0x1b63
clr.dll!LogHelp_LogAssert+0x1a80
clr.dll!LogHelp_LogAssert+0x2320
clr.dll!MetaDataGetDispenser+0x12efa
clr.dll!LogHelp_LogAssert+0x2f08
clr.dll!LogHelp_LogAssert+0x2e73
clr.dll!LogHelp_LogAssert+0x2db2
clr.dll!LogHelp_LogAssert+0x5cc5
clr.dll!LogHelp_LogAssert+0x5dbb
clr.dll!LogHelp_LogAssert+0x5d17
clr.dll!LogHelp_LogAssert+0x2e73
clr.dll!LogHelp_LogAssert+0x2db2
clr.dll!LogHelp_LogAssert+0x2fa3
clr.dll!MetaDataGetDispenser+0x12e47
clr.dll!LogHelp_LogAssert+0x2abf
clr.dll!LogHelp_LogAssert+0x298f
clr.dll!DllCanUnloadNowInternal+0xca5
KERNEL32.dll!BaseThreadInitThunk+0x14
ntdll.dll!RtlUserThreadStart+0x21

And a second time I used WinDbg to find out the stack of devenv.exe, when this issue occurred on it.

Current frame: (MethodDesc 00007ffdd64d3648 +0xbe System.Collections.Generic.HashSet`1[[System.__Canon, mscorlib]].Contains(System.__Canon))
Child-SP         RetAddr          Caller, Callee
000000808fc3c950 00007ffde40610c3 (MethodDesc 00007ffde1cb9f28 +0x23 Microsoft.CodeAnalysis.Diagnostics.AnalyzerExecutor.ShouldExecuteNode(SyntaxNodeAnalyzerStateData, Microsoft.CodeAnalysis.SyntaxNode, Microsoft.CodeAnalysis.Diagnostics.DiagnosticAnalyzer))
000000808fc3c9a0 00007ffde4060f5d (MethodDesc 00007ffde42aa148 +0xfd Microsoft.CodeAnalysis.Diagnostics.AnalyzerExecutor.ExecuteSyntaxNodeActions[[Microsoft.CodeAnalysis.CSharp.SyntaxKind, Microsoft.CodeAnalysis.CSharp]](System.Collections.Generic.IEnumerable`1<Microsoft.CodeAnalysis.SyntaxNode>, Microsoft.CodeAnalysis.Collections.ImmutableSegmentedDictionary`2<Microsoft.CodeAnalysis.CSharp.SyntaxKind,System.Collections.Immutable.ImmutableArray`1<Microsoft.CodeAnalysis.Diagnostics.SyntaxNodeAnalyzerAction`1<Microsoft.CodeAnalysis.CSharp.SyntaxKind>>>, Microsoft.CodeAnalysis.Diagnostics.DiagnosticAnalyzer, Microsoft.CodeAnalysis.ISymbol, Microsoft.CodeAnalysis.SemanticModel, System.Func`2<Microsoft.CodeAnalysis.SyntaxNode,Microsoft.CodeAnalysis.CSharp.SyntaxKind>, System.Action`1<Microsoft.CodeAnalysis.Diagnostic>, System.Func`2<Microsoft.CodeAnalysis.Diagnostic,Boolean>, Boolean, SyntaxNodeAnalyzerStateData))
000000808fc3c9b0 00007ffddade46b0 (MethodDesc 00007ffddb55c6a0 +0x20 Microsoft.CodeAnalysis.PooledObjects.ObjectPool`1[[System.__Canon, mscorlib]].Allocate())
000000808fc3c9f0 00007ffde3b3fc59 (MethodDesc 00007ffde3e65058 +0x89 Microsoft.CodeAnalysis.PooledObjects.PooledDelegates.GetPooledDelegate[[System.__Canon, mscorlib],[System.ValueTuple`2[[System.__Canon, mscorlib],[System.__Canon, mscorlib]], mscorlib],[System.__Canon, mscorlib],[System.__Canon, mscorlib]](System.__Canon, System.ValueTuple`2<System.__Canon,System.__Canon>, System.__Canon ByRef))
000000808fc3ca50 00007ffde4060c76 (MethodDesc 00007ffde42a8168 +0x1f6 Microsoft.CodeAnalysis.Diagnostics.AnalyzerExecutor.ExecuteSyntaxNodeActionsCore[[Microsoft.CodeAnalysis.CSharp.SyntaxKind, Microsoft.CodeAnalysis.CSharp]](System.Collections.Generic.IEnumerable`1<Microsoft.CodeAnalysis.SyntaxNode>, Microsoft.CodeAnalysis.Collections.ImmutableSegmentedDictionary`2<Microsoft.CodeAnalysis.CSharp.SyntaxKind,System.Collections.Immutable.ImmutableArray`1<Microsoft.CodeAnalysis.Diagnostics.SyntaxNodeAnalyzerAction`1<Microsoft.CodeAnalysis.CSharp.SyntaxKind>>>, Microsoft.CodeAnalysis.Diagnostics.DiagnosticAnalyzer, Microsoft.CodeAnalysis.ISymbol, Microsoft.CodeAnalysis.SemanticModel, System.Func`2<Microsoft.CodeAnalysis.SyntaxNode,Microsoft.CodeAnalysis.CSharp.SyntaxKind>, Microsoft.CodeAnalysis.Text.TextSpan, SyntaxNodeAnalyzerStateData, Boolean))
000000808fc3cb60 00007ffde406040a (MethodDesc 00007ffde427f228 +0xda Microsoft.CodeAnalysis.Diagnostics.AnalyzerExecutor.TryExecuteSyntaxNodeActions[[Microsoft.CodeAnalysis.CSharp.SyntaxKind, Microsoft.CodeAnalysis.CSharp]](System.Collections.Generic.IEnumerable`1<Microsoft.CodeAnalysis.SyntaxNode>, Microsoft.CodeAnalysis.Collections.ImmutableSegmentedDictionary`2<Microsoft.CodeAnalysis.CSharp.SyntaxKind,System.Collections.Immutable.ImmutableArray`1<Microsoft.CodeAnalysis.Diagnostics.SyntaxNodeAnalyzerAction`1<Microsoft.CodeAnalysis.CSharp.SyntaxKind>>>, Microsoft.CodeAnalysis.Diagnostics.DiagnosticAnalyzer, Microsoft.CodeAnalysis.SemanticModel, System.Func`2<Microsoft.CodeAnalysis.SyntaxNode,Microsoft.CodeAnalysis.CSharp.SyntaxKind>, Microsoft.CodeAnalysis.Text.TextSpan, Int32, Microsoft.CodeAnalysis.ISymbol, Microsoft.CodeAnalysis.Diagnostics.AnalysisScope, Microsoft.CodeAnalysis.Diagnostics.AnalysisState, Boolean))
000000808fc3cc10 00007ffde4059942 (MethodDesc 00007ffde4276060 +0x232 Microsoft.CodeAnalysis.Diagnostics.AnalyzerDriver`1+<>c__DisplayClass12_0[[Microsoft.CodeAnalysis.CSharp.SyntaxKind, Microsoft.CodeAnalysis.CSharp]].<TryExecuteDeclaringReferenceActions>g__executeNodeActionsByKind|2(Microsoft.CodeAnalysis.Diagnostics.AnalysisScope, System.Collections.Immutable.ImmutableArray`1<Microsoft.CodeAnalysis.SyntaxNode>, GroupedAnalyzerActions<Microsoft.CodeAnalysis.CSharp.SyntaxKind>))
000000808fc3cd60 00007ffde405832a (MethodDesc 00007ffde4276058 +0x2a Microsoft.CodeAnalysis.Diagnostics.AnalyzerDriver`1+<>c__DisplayClass12_0[[Microsoft.CodeAnalysis.CSharp.SyntaxKind, Microsoft.CodeAnalysis.CSharp]].<TryExecuteDeclaringReferenceActions>g__executeNodeActions|1())
000000808fc3cda0 00007ffde4052b79 (MethodDesc 00007ffde3d22b68 +0x2c9 Microsoft.CodeAnalysis.Diagnostics.AnalyzerDriver`1[[Microsoft.CodeAnalysis.CSharp.SyntaxKind, Microsoft.CodeAnalysis.CSharp]].TryExecuteDeclaringReferenceActions(Microsoft.CodeAnalysis.SyntaxReference, Int32, Microsoft.CodeAnalysis.Diagnostics.SymbolDeclaredCompilationEvent, Microsoft.CodeAnalysis.Diagnostics.AnalysisScope, Microsoft.CodeAnalysis.Diagnostics.AnalysisState, GroupedAnalyzerActions<Microsoft.CodeAnalysis.CSharp.SyntaxKind>, GroupedAnalyzerActions<Microsoft.CodeAnalysis.CSharp.SyntaxKind>, Boolean, Boolean, Boolean, Boolean, Boolean, System.Threading.CancellationToken))
000000808fc3ce40 00007ffde4050f10 (MethodDesc 00007ffde3d22b48 +0x420 Microsoft.CodeAnalysis.Diagnostics.AnalyzerDriver`1[[Microsoft.CodeAnalysis.CSharp.SyntaxKind, Microsoft.CodeAnalysis.CSharp]].TryExecuteDeclaringReferenceActions(Microsoft.CodeAnalysis.Diagnostics.SymbolDeclaredCompilationEvent, Microsoft.CodeAnalysis.Diagnostics.AnalysisScope, Microsoft.CodeAnalysis.Diagnostics.AnalysisState, Boolean, IGroupedAnalyzerActions, System.Threading.CancellationToken))
000000808fc3d030 00007ffde404c61c (MethodDesc 00007ffde4251b40 +0x40c Microsoft.CodeAnalysis.Diagnostics.AnalyzerDriver+<TryProcessSymbolDeclaredAsync>d__133.MoveNext())
000000808fc3d078 00007ffe333ee719 (MethodDesc 00007ffe32737658 +0x49 System.Threading.AsyncLocalValueMap+MultiElementAsyncLocalValueMap.TryGetValue(System.Threading.IAsyncLocal, System.Object ByRef))
000000808fc3d1e0 00007ffde404c19a (MethodDesc 00007ffde42572c0 +0x7a System.Runtime.CompilerServices.AsyncTaskMethodBuilder`1[[System.__Canon, mscorlib]].Start[[Microsoft.CodeAnalysis.Diagnostics.AnalyzerDriver+<TryProcessSymbolDeclaredAsync>d__133, Microsoft.CodeAnalysis]](<TryProcessSymbolDeclaredAsync>d__133 ByRef))
000000808fc3d290 00007ffde404c0db (MethodDesc 00007ffde20d2ff0 +0x8b Microsoft.CodeAnalysis.Diagnostics.AnalyzerDriver.TryProcessSymbolDeclaredAsync(Microsoft.CodeAnalysis.Diagnostics.SymbolDeclaredCompilationEvent, Microsoft.CodeAnalysis.Diagnostics.AnalysisScope, Microsoft.CodeAnalysis.Diagnostics.AnalysisState, System.Threading.CancellationToken))
000000808fc3d2b0 00007ffe329dd05f (MethodDesc 00007ffe325c3680 +0xbf System.Runtime.CompilerServices.AsyncMethodBuilderCore+MoveNextRunner.Run())
000000808fc3d340 00007ffde4047de4 (MethodDesc 00007ffde4250d08 +0x1e4 Microsoft.CodeAnalysis.Diagnostics.AnalyzerDriver+<TryProcessEventCoreAsync>d__132.MoveNext())
000000808fc3d460 00007ffde4047b8a (MethodDesc 00007ffde42518a0 +0x7a System.Runtime.CompilerServices.AsyncTaskMethodBuilder`1[[System.__Canon, mscorlib]].Start[[Microsoft.CodeAnalysis.Diagnostics.AnalyzerDriver+<TryProcessEventCoreAsync>d__132, Microsoft.CodeAnalysis]](<TryProcessEventCoreAsync>d__132 ByRef))
000000808fc3d480 00007ffdd658f6f0 (MethodDesc 00007ffdd6609970 +0x200 System.Collections.Concurrent.ConcurrentDictionary`2[[System.Int32, mscorlib],[System.Nullable`1[[Microsoft.VisualStudio.Threading.JoinableTaskInternals+JoinableTaskToken, Microsoft.VisualStudio.Threading]], mscorlib]].TryRemoveInternal(Int32, System.Nullable`1<JoinableTaskToken> ByRef, Boolean, System.Nullable`1<JoinableTaskToken>))
000000808fc3d510 00007ffde4047acb (MethodDesc 00007ffde20d2fe0 +0x8b Microsoft.CodeAnalysis.Diagnostics.AnalyzerDriver.TryProcessEventCoreAsync(Microsoft.CodeAnalysis.Diagnostics.CompilationEvent, Microsoft.CodeAnalysis.Diagnostics.AnalysisScope, Microsoft.CodeAnalysis.Diagnostics.AnalysisState, System.Threading.CancellationToken))
000000808fc3d520 00007ffdd658f103 (MethodDesc 00007ffdd6609968 +0x33 System.Collections.Concurrent.ConcurrentDictionary`2[[System.Int32, mscorlib],[System.Nullable`1[[Microsoft.VisualStudio.Threading.JoinableTaskInternals+JoinableTaskToken, Microsoft.VisualStudio.Threading]], mscorlib]].TryRemove(Int32, System.Nullable`1<JoinableTaskToken> ByRef))
000000808fc3d5c0 00007ffde404763f (MethodDesc 00007ffde3e60788 +0x8f Microsoft.CodeAnalysis.Diagnostics.AnalyzerDriver+<ProcessEventAsync>d__130.MoveNext())
000000808fc3d700 00007ffde4047540 (MethodDesc 00007ffde4250858 +0x80 System.Runtime.CompilerServices.AsyncTaskMethodBuilder.Start[[Microsoft.CodeAnalysis.Diagnostics.AnalyzerDriver+<ProcessEventAsync>d__130, Microsoft.CodeAnalysis]](<ProcessEventAsync>d__130 ByRef))
000000808fc3d7b0 00007ffde4047490 (MethodDesc 00007ffde20d2fc0 +0x70 Microsoft.CodeAnalysis.Diagnostics.AnalyzerDriver.ProcessEventAsync(Microsoft.CodeAnalysis.Diagnostics.CompilationEvent, Microsoft.CodeAnalysis.Diagnostics.AnalysisScope, Microsoft.CodeAnalysis.Diagnostics.AnalysisState, System.Threading.CancellationToken))
000000808fc3d7c0 00007ffde3b345df (MethodDesc 00007ffddb9e02a8 +0x7f Microsoft.CodeAnalysis.Diagnostics.AsyncQueue`1[[System.__Canon, mscorlib]].get_Count())
000000808fc3d860 00007ffde3b3b616 (MethodDesc 00007ffde3e60210 +0x456 Microsoft.CodeAnalysis.Diagnostics.AnalyzerDriver+<ProcessCompilationEventsCoreAsync>d__129.MoveNext())
000000808fc3da00 00007ffde3b3b14a (MethodDesc 00007ffde3e60cb0 +0x7a System.Runtime.CompilerServices.AsyncTaskMethodBuilder`1[[System.__Canon, mscorlib]].Start[[Microsoft.CodeAnalysis.Diagnostics.AnalyzerDriver+<ProcessCompilationEventsCoreAsync>d__129, Microsoft.CodeAnalysis]](<ProcessCompilationEventsCoreAsync>d__129 ByRef))
000000808fc3dab0 00007ffde3b3b08d (MethodDesc 00007ffde20d2fb0 +0x7d Microsoft.CodeAnalysis.Diagnostics.AnalyzerDriver.ProcessCompilationEventsCoreAsync(Microsoft.CodeAnalysis.Diagnostics.AnalysisScope, Microsoft.CodeAnalysis.Diagnostics.AnalysisState, Boolean, System.Threading.CancellationToken))
000000808fc3db60 00007ffde3b3abb1 (MethodDesc 00007ffde3e3f478 +0x531 Microsoft.CodeAnalysis.Diagnostics.AnalyzerDriver+<ProcessCompilationEventsAsync>d__128.MoveNext())
000000808fc3dc40 00007ffde3b3a200 (MethodDesc 00007ffde3e3f6d0 +0x80 System.Runtime.CompilerServices.AsyncTaskMethodBuilder.Start[[Microsoft.CodeAnalysis.Diagnostics.AnalyzerDriver+<ProcessCompilationEventsAsync>d__128, Microsoft.CodeAnalysis]](<ProcessCompilationEventsAsync>d__128 ByRef))
000000808fc3dc50 00007ffdd658f103 (MethodDesc 00007ffdd6609968 +0x33 System.Collections.Concurrent.ConcurrentDictionary`2[[System.Int32, mscorlib],[System.Nullable`1[[Microsoft.VisualStudio.Threading.JoinableTaskInternals+JoinableTaskToken, Microsoft.VisualStudio.Threading]], mscorlib]].TryRemove(Int32, System.Nullable`1<JoinableTaskToken> ByRef))
000000808fc3dc70 00007ffde3ad529f (MethodDesc 00007ffde1cb9a98 +0x16f Microsoft.CodeAnalysis.Diagnostics.AnalyzerExecutor..ctor(Microsoft.CodeAnalysis.Compilation, Microsoft.CodeAnalysis.Diagnostics.AnalyzerOptions, System.Action`1<Microsoft.CodeAnalysis.Diagnostic>, System.Action`3<System.Exception,Microsoft.CodeAnalysis.Diagnostics.DiagnosticAnalyzer,Microsoft.CodeAnalysis.Diagnostic>, System.Func`2<System.Exception,Boolean>, System.Func`2<Microsoft.CodeAnalysis.Diagnostics.DiagnosticAnalyzer,Boolean>, Microsoft.CodeAnalysis.Diagnostics.AnalyzerManager, System.Func`2<Microsoft.CodeAnalysis.Diagnostics.DiagnosticAnalyzer,Boolean>, System.Func`5<Microsoft.CodeAnalysis.Diagnostic,Microsoft.CodeAnalysis.Diagnostics.DiagnosticAnalyzer,Microsoft.CodeAnalysis.Compilation,System.Threading.CancellationToken,Boolean>, System.Func`3<Microsoft.CodeAnalysis.SyntaxTree,Microsoft.CodeAnalysis.Text.TextSpan,Boolean>, System.Func`4<Microsoft.CodeAnalysis.Diagnostics.DiagnosticAnalyzer,Microsoft.CodeAnalysis.SyntaxTree,Microsoft.CodeAnalysis.SyntaxTreeOptionsProvider,Boolean>, System.Func`2<Microsoft.CodeAnalysis.Diagnostics.DiagnosticAnalyzer,System.Object>, System.Func`2<Microsoft.CodeAnalysis.SyntaxTree,Microsoft.CodeAnalysis.SemanticModel>, System.Collections.Concurrent.ConcurrentDictionary`2<Microsoft.CodeAnalysis.Diagnostics.DiagnosticAnalyzer,System.Runtime.CompilerServices.StrongBox`1<Int64>>, System.Action`3<Microsoft.CodeAnalysis.Diagnostic,Microsoft.CodeAnalysis.Diagnostics.DiagnosticAnalyzer,Boolean>, System.Action`2<Microsoft.CodeAnalysis.Diagnostic,Microsoft.CodeAnalysis.Diagnostics.DiagnosticAnalyzer>, System.Action`1<Microsoft.CodeAnalysis.Diagnostics.Suppression>, System.Threading.CancellationToken))
000000808fc3dcf0 00007ffde3b3a146 (MethodDesc 00007ffde20d2fa0 +0x76 Microsoft.CodeAnalysis.Diagnostics.AnalyzerDriver.ProcessCompilationEventsAsync(Microsoft.CodeAnalysis.Diagnostics.AnalysisScope, Microsoft.CodeAnalysis.Diagnostics.AnalysisState, Boolean, System.Threading.CancellationToken))
000000808fc3ddb0 00007ffde3b39f40 (MethodDesc 00007ffde3e3f0a8 +0x1c0 Microsoft.CodeAnalysis.Diagnostics.AnalyzerDriver+<ExecutePrimaryAnalysisTaskAsync>d__96.MoveNext())
000000808fc3de40 00007ffde3b39d10 (MethodDesc 00007ffde3e3f280 +0x80 System.Runtime.CompilerServices.AsyncTaskMethodBuilder.Start[[Microsoft.CodeAnalysis.Diagnostics.AnalyzerDriver+<ExecutePrimaryAnalysisTaskAsync>d__96, Microsoft.CodeAnalysis]](<ExecutePrimaryAnalysisTaskAsync>d__96 ByRef))
000000808fc3def0 00007ffde3b39c60 (MethodDesc 00007ffde20d2dd0 +0x70 Microsoft.CodeAnalysis.Diagnostics.AnalyzerDriver.ExecutePrimaryAnalysisTaskAsync(Microsoft.CodeAnalysis.Diagnostics.AnalysisScope, Microsoft.CodeAnalysis.Diagnostics.AnalysisState, Boolean, System.Threading.CancellationToken))
000000808fc3df80 00007ffde3b3998f (MethodDesc 00007ffde3e3ed88 +0xff Microsoft.CodeAnalysis.Diagnostics.AnalyzerDriver+<AttachQueueAndProcessAllEventsAsync>d__94.MoveNext())
000000808fc3dfa0 00007ffdd658f762 (MethodDesc 00007ffdd6609970 +0x272 System.Collections.Concurrent.ConcurrentDictionary`2[[System.Int32, mscorlib],[System.Nullable`1[[Microsoft.VisualStudio.Threading.JoinableTaskInternals+JoinableTaskToken, Microsoft.VisualStudio.Threading]], mscorlib]].TryRemoveInternal(Int32, System.Nullable`1<JoinableTaskToken> ByRef, Boolean, System.Nullable`1<JoinableTaskToken>))
000000808fc3e050 00007ffde3b39820 (MethodDesc 00007ffde3e3ef60 +0x80 System.Runtime.CompilerServices.AsyncTaskMethodBuilder.Start[[Microsoft.CodeAnalysis.Diagnostics.AnalyzerDriver+<AttachQueueAndProcessAllEventsAsync>d__94, Microsoft.CodeAnalysis]](<AttachQueueAndProcessAllEventsAsync>d__94 ByRef))
000000808fc3e100 00007ffde3b3976d (MethodDesc 00007ffde20d2db0 +0x6d Microsoft.CodeAnalysis.Diagnostics.AnalyzerDriver.AttachQueueAndProcessAllEventsAsync(Microsoft.CodeAnalysis.Diagnostics.AsyncQueue`1<Microsoft.CodeAnalysis.Diagnostics.CompilationEvent>, Microsoft.CodeAnalysis.Diagnostics.AnalysisScope, Microsoft.CodeAnalysis.Diagnostics.AnalysisState, System.Threading.CancellationToken))
000000808fc3e110 00007ffdd6337415 (MethodDesc 00007ffdd64d37e0 +0x55 System.Collections.Generic.HashSet`1[[System.__Canon, mscorlib]].InternalGetHashCode(System.__Canon))
000000808fc3e190 00007ffde3b38f9c (MethodDesc 00007ffde3e3e930 +0xbc Microsoft.CodeAnalysis.Diagnostics.CompilationWithAnalyzers+<ComputeAnalyzerDiagnosticsCoreAsync>d__72.MoveNext())
000000808fc3e1b0 00007ffe3331b878 (MethodDesc 00007ffe3274a038 +0x1b8 System.Threading.SemaphoreSlim.Release(Int32))
000000808fc3e1c0 00007ffdd854776e (MethodDesc 00007ffdd88ff358 +0x19e System.Collections.Immutable.ImmutableExtensions.ToArray[[System.__Canon, mscorlib]](System.Collections.Generic.IEnumerable`1<System.__Canon>, Int32))
000000808fc3e240 00007ffde3b38e70 (MethodDesc 00007ffde3e3eb08 +0x80 System.Runtime.CompilerServices.AsyncTaskMethodBuilder.Start[[Microsoft.CodeAnalysis.Diagnostics.CompilationWithAnalyzers+<ComputeAnalyzerDiagnosticsCoreAsync>d__72, Microsoft.CodeAnalysis]](<ComputeAnalyzerDiagnosticsCoreAsync>d__72 ByRef))
000000808fc3e250 00007ffde1ea404f (MethodDesc 00007ffddb9e02c0 +0x1ef Microsoft.CodeAnalysis.Diagnostics.AsyncQueue`1[[System.__Canon, mscorlib]].EnqueueCore(System.__Canon))
000000808fc3e260 00007ffdd6339dfa (MethodDesc 00007ffdd650c5b8 +0x6a System.Collections.Generic.Queue`1[[System.__Canon, mscorlib]].Enqueue(System.__Canon))
000000808fc3e2f0 00007ffde3b38dbd (MethodDesc 00007ffdde1a4a88 +0x6d Microsoft.CodeAnalysis.Diagnostics.CompilationWithAnalyzers.ComputeAnalyzerDiagnosticsCoreAsync(Microsoft.CodeAnalysis.Diagnostics.AnalyzerDriver, Microsoft.CodeAnalysis.Diagnostics.AsyncQueue`1<Microsoft.CodeAnalysis.Diagnostics.CompilationEvent>, Microsoft.CodeAnalysis.Diagnostics.AnalysisScope, System.Threading.CancellationToken))
000000808fc3e380 00007ffde3b38a3a (MethodDesc 00007ffde3e3e680 +0x11a Microsoft.CodeAnalysis.Diagnostics.CompilationWithAnalyzers+<>c__DisplayClass67_1+<<ComputeAnalyzerDiagnosticsAsync>b__1>d.MoveNext())
000000808fc3e398 00007ffdd658dd01 (MethodDesc 00007ffdd660b610 +0x71 DomainNeutralILStubClass.IL_STUB_PInvoke())
000000808fc3e410 00007ffde3b388b0 (MethodDesc 00007ffde3e3e7e8 +0x80 System.Runtime.CompilerServices.AsyncTaskMethodBuilder.Start[[Microsoft.CodeAnalysis.Diagnostics.CompilationWithAnalyzers+<>c__DisplayClass67_1+<<ComputeAnalyzerDiagnosticsAsync>b__1>d, Microsoft.CodeAnalysis]](<<ComputeAnalyzerDiagnosticsAsync>b__1>d ByRef))
000000808fc3e420 00007ffdd658db72 (MethodDesc 00007ffdd64bda00 +0x72 Microsoft.VisualStudio.Services.VsHostExecutionContextEvents.OnSetHostExecutionContext())
000000808fc3e440 00007ffe329b7570 (MethodDesc 00007ffe326ffef8 +0x10 System.Threading.HostExecutionContextManager.CheckIfHosted())
000000808fc3e4c0 00007ffde3b387fe (MethodDesc 00007ffde3d21230 +0x4e Microsoft.CodeAnalysis.Diagnostics.CompilationWithAnalyzers+<>c__DisplayClass67_1.<ComputeAnalyzerDiagnosticsAsync>b__1())
000000808fc3e540 00007ffe329dbe4e (MethodDesc 00007ffe325c4448 +0x4e System.Threading.Tasks.Task`1[[System.__Canon, mscorlib]].InnerInvoke())
000000808fc3e590 00007ffe329daf27 (MethodDesc 00007ffe325d08a0 +0x47 System.Threading.Tasks.Task.Execute())
000000808fc3e5a0 00007ffe329db335 (MethodDesc 00007ffe325d0910 +0x15 System.Threading.Tasks.Task.ExecutionContextCallback(System.Object))
000000808fc3e5d0 00007ffe3296df12 (MethodDesc 00007ffe323e85b8 +0x172 System.Threading.ExecutionContext.RunInternal(System.Threading.ExecutionContext, System.Threading.ContextCallback, System.Object, Boolean))
000000808fc3e5e0 00007ffe32946fbe (MethodDesc 00007ffe325d0a78 +0x47e System.Threading.Tasks.Task.FinishContinuations())
000000808fc3e6a0 00007ffe3296dd95 (MethodDesc 00007ffe325c87a0 +0x15 System.Threading.ExecutionContext.Run(System.Threading.ExecutionContext, System.Threading.ContextCallback, System.Object, Boolean))
000000808fc3e6d0 00007ffe329db1e1 (MethodDesc 00007ffe325d0cf8 +0x231 System.Threading.Tasks.Task.ExecuteWithThreadLocal(System.Threading.Tasks.Task ByRef))
000000808fc3e720 00007ffe32938c92 (MethodDesc 00007ffe326e6a58 +0x22 System.Threading.ThreadPoolWorkQueue.EnsureThreadRequested())
000000808fc3e780 00007ffe329da8c1 (MethodDesc 00007ffe325d0900 +0xa1 System.Threading.Tasks.Task.ExecuteEntry(Boolean))
000000808fc3e7c0 00007ffe32938e46 (MethodDesc 00007ffe326e6aa8 +0x156 System.Threading.ThreadPoolWorkQueue.Dispatch())

From the above stack trace, I suspected that the HashSet in trouble was still checking whether an element was inside it in Microsoft.CodeAnalysis.Diagnostics.AnalyzerExecutor.ExecuteSyntaxNodeActions, however, the same HashSet was Cleared by another thread, thus this thread ran into an infinite loop.

Please have this issue fixed.

[wmjordan]

@pawchen I’ve hereby written a thing to monitor the system CPU usage merely for this bug. You can download the extension and turn on the CPU monitoring feature on VS.

[wmjordan]

@sharwell

Yes, it is the issue. Sorry for having brought trouble to you. They said that issue had been fixed.