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Fix EventSource shutdown deadlock #56453

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Merged
merged 1 commit into from
Jul 29, 2021
Merged

Fix EventSource shutdown deadlock #56453

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2 changes: 2 additions & 0 deletions src/libraries/System.Private.CoreLib/src/System/Diagnostics/Tracing/EventProvider.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -7,6 +7,7 @@
using System.Globalization;
using System.Numerics;
using System.Runtime.InteropServices;
using System.Threading;

#if ES_BUILD_STANDALONE
using Microsoft.Win32;
Expand Down Expand Up @@ -209,6 +210,7 @@ protected virtual void Dispose(bool disposing)
// deadlocks in race conditions (dispose racing with an ETW command).
//
// We solve by Unregistering after releasing the EventListenerLock.
Debug.Assert(!Monitor.IsEntered(EventListener.EventListenersLock));
if (registrationHandle != 0)
EventUnregister(registrationHandle);
}
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18 changes: 16 additions & 2 deletions src/libraries/System.Private.CoreLib/src/System/Diagnostics/Tracing/EventSource.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -1449,6 +1449,10 @@ protected virtual void Dispose(bool disposing)
return;
}

// Do not invoke Dispose under the lock as this can lead to a deadlock.
// See https://github.com/dotnet/runtime/issues/48342 for details.
Debug.Assert(!Monitor.IsEntered(EventListener.EventListenersLock));

if (disposing)
{
#if FEATURE_MANAGED_ETW
Expand Down Expand Up @@ -4274,16 +4278,26 @@ internal static void DisposeOnShutdown()
#endif
{
Debug.Assert(EventSource.IsSupported);

List<EventSource> sourcesToDispose = new List<EventSource>();
lock (EventListenersLock)
{
Debug.Assert(s_EventSources != null);
foreach (WeakReference<EventSource> esRef in s_EventSources)
{
if (esRef.TryGetTarget(out EventSource? es))
es.Dispose();
{
sourcesToDispose.Add(es);
}
}
}

// Do not invoke Dispose under the lock as this can lead to a deadlock.
// See https://github.com/dotnet/runtime/issues/48342 for details.
Debug.Assert(!Monitor.IsEntered(EventListenersLock));
foreach (EventSource es in sourcesToDispose)
{
es.Dispose();
}
}

/// <summary>
Expand Down