Set the async local just before execution

src/libraries/Microsoft.Extensions.HostFactoryResolver/src/HostFactoryResolver.cs

@@ -194,10 +194,6 @@ public HostingListener(string[] args, MethodInfo entryPoint, TimeSpan waitTimeou
 
             public object CreateHost()
             {
-                // Set the async local to the instance of the HostingListener so we can filter events that
-                // aren't scoped to this execution of the entry point.
-                _currentListener.Value = this;
-
                 using var subscription = DiagnosticListener.AllListeners.Subscribe(this);
 
                 // Kick off the entry point on a new thread so we don't block the current one
@@ -208,6 +204,10 @@ public object CreateHost()
 
                     try
                     {
+                        // Set the async local to the instance of the HostingListener so we can filter events that
+                        // aren't scoped to this execution of the entry point.
+                        _currentListener.Value = this;
+
                         var parameters = _entryPoint.GetParameters();
                         if (parameters.Length == 0)
                         {

src/libraries/Microsoft.Extensions.HostFactoryResolver/tests/HostFactoryResolverTests.cs

@@ -6,6 +6,7 @@
 using System.Diagnostics.CodeAnalysis;
 using System.Reflection;
 using System.Threading;
+using System.Threading.Tasks;
 using Xunit;
 
 namespace Microsoft.Extensions.Hosting.Tests
@@ -250,5 +251,27 @@ public void TopLevelStatements()
             Assert.NotNull(factory);
             Assert.IsAssignableFrom<IServiceProvider>(factory(Array.Empty<string>()));
         }
+
+        [ConditionalFact(typeof(PlatformDetection), nameof(PlatformDetection.IsThreadingSupported))]
+        [DynamicDependency(DynamicallyAccessedMemberTypes.All, typeof(NoSpecialEntryPointPattern.Program))]
+        public void NoSpecialEntryPointPatternCanRunInParallel()
+        {
+            var factory = HostFactoryResolver.ResolveServiceProviderFactory(typeof(NoSpecialEntryPointPattern.Program).Assembly, s_WaitTimeout);
+            Assert.NotNull(factory);
+
+            var tasks = new Task<IServiceProvider>[30];
+            int index = 0;
+            for (int i = 0; i < tasks.Length; i++)
+            {
+                tasks[index++] = Task.Run(() => factory(Array.Empty<string>()));
+            }
+
+            Task.WaitAll(tasks);
+
+            foreach (var t in tasks)
+            {
+                Assert.IsAssignableFrom<IServiceProvider>(t.Result);
+            }
+        }
     }
 }

src/libraries/Microsoft.Extensions.HostFactoryResolver/tests/NoSpecialEntryPointPatternHangs/Program.cs

@@ -9,7 +9,7 @@ public class Program
     {
         public static void Main(string[] args)
         {
-            Console.ReadLine();
+            System.Threading.Thread.Sleep(-1);
         }
     }
 }