[6.0] Check for pending IO in the portable thread pool's worker threads (#82248)

* [6.0] Check for pending IO in the portable thread pool's worker threads

- Port of #82245
- When Resource Monitor is attached, some async IO operations are bound to the thread that issued it even though the IO handle is bound to an IOCP. If the thread exits, the async IO operation is aborted. This can lead to hangs or unexpected exceptions.
- Added a check that was missing in the portable thread pool implementation to prevent exiting a worker thread when it has pending IO

Port of fix for #82207

* Refactor Windows-specific code

Author: kouvel

src/libraries/Common/src/Interop/Windows/Kernel32/Interop.Threading.cs

@@ -71,5 +71,9 @@ internal enum ThreadPriority : int
 
         [DllImport(Libraries.Kernel32)]
         internal static extern bool SetThreadPriority(SafeWaitHandle hThread, int nPriority);
+
+        [DllImport(Libraries.Kernel32, SetLastError = true)]
+        [return: MarshalAs(UnmanagedType.Bool)]
+        internal static extern bool GetThreadIOPendingFlag(nint hThread, out BOOL lpIOIsPending);
     }
 }

src/libraries/System.Private.CoreLib/src/System.Private.CoreLib.Shared.projitems

@@ -1684,6 +1684,9 @@
     <Compile Include="$(CommonPath)Interop\Windows\Kernel32\Interop.SystemTimeToFileTime.cs">
       <Link>Common\Interop\Windows\Kernel32\Interop.SystemTimeToFileTime.cs</Link>
     </Compile>
+    <Compile Include="$(CommonPath)Interop\Windows\Kernel32\Interop.Threading.cs">
+      <Link>Common\Interop\Windows\Kernel32\Interop.Threading.cs</Link>
+    </Compile>
     <Compile Include="$(CommonPath)Interop\Windows\Kernel32\Interop.TimeZone.cs">
       <Link>Common\Interop\Windows\Kernel32\Interop.TimeZone.cs</Link>
     </Compile>
@@ -2268,8 +2271,8 @@
     <Compile Include="$(MSBuildThisFileDirectory)System\Threading\PortableThreadPool.WaitThread.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)System\Threading\PortableThreadPool.WorkerThread.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)System\Threading\PortableThreadPool.WorkerTracking.cs" />
-    <Compile Include="$(MSBuildThisFileDirectory)System\Threading\PortableThreadPool.CpuUtilizationReader.Unix.cs" Condition="'$(TargetsUnix)' == 'true' or '$(TargetsBrowser)' == 'true'" />
-    <Compile Include="$(MSBuildThisFileDirectory)System\Threading\PortableThreadPool.CpuUtilizationReader.Windows.cs" Condition="'$(TargetsWindows)' == 'true'" />
+    <Compile Include="$(MSBuildThisFileDirectory)System\Threading\PortableThreadPool.Unix.cs" Condition="'$(TargetsUnix)' == 'true' or '$(TargetsBrowser)' == 'true'" />
+    <Compile Include="$(MSBuildThisFileDirectory)System\Threading\PortableThreadPool.Windows.cs" Condition="'$(TargetsWindows)' == 'true'" />
     <Compile Include="$(MSBuildThisFileDirectory)System\Threading\LowLevelLifoSemaphore.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)System\Threading\LowLevelLifoSemaphore.Windows.cs" Condition="'$(TargetsWindows)' == 'true'" />
     <Compile Include="$(MSBuildThisFileDirectory)System\Threading\RegisteredWaitHandle.Portable.cs" />
@@ -2301,9 +2304,6 @@
   <ItemGroup Condition="'$(FeatureCoreCLR)' != 'true' and '$(TargetsWindows)' == 'true'">
     <Compile Include="$(MSBuildThisFileDirectory)System\Threading\Thread.Windows.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)System\Threading\WaitHandle.Windows.cs" />
-    <Compile Include="$(CommonPath)\Interop\Windows\Kernel32\Interop.Threading.cs">
-      <Link>Interop\Windows\Kernel32\Interop.Threading.cs</Link>
-    </Compile>
   </ItemGroup>
   <ItemGroup Condition="'$(FeatureGenericMath)' == 'true'">
     <Compile Include="$(MSBuildThisFileDirectory)System\IAdditionOperators.cs" />

src/libraries/System.Private.CoreLib/src/System/Threading/PortableThreadPool.CpuUtilizationReader.Unix.cs renamed to src/libraries/System.Private.CoreLib/src/System/Threading/PortableThreadPool.Unix.cs

@@ -5,6 +5,11 @@ namespace System.Threading
 {
     internal sealed partial class PortableThreadPool
     {
+        private static partial class WorkerThread
+        {
+            private static bool IsIOPending => false;
+        }
+
         private struct CpuUtilizationReader
         {
             private Interop.Sys.ProcessCpuInformation _cpuInfo;

src/libraries/System.Private.CoreLib/src/System/Threading/PortableThreadPool.CpuUtilizationReader.Windows.cs renamed to src/libraries/System.Private.CoreLib/src/System/Threading/PortableThreadPool.Windows.cs

@@ -8,6 +8,20 @@ namespace System.Threading
 {
     internal sealed partial class PortableThreadPool
     {
+        private static partial class WorkerThread
+        {
+            private static bool IsIOPending
+            {
+                get
+                {
+                    bool success =
+                        Interop.Kernel32.GetThreadIOPendingFlag(Interop.Kernel32.GetCurrentThread(), out Interop.BOOL isIOPending);
+                    Debug.Assert(success);
+                    return !success || isIOPending != Interop.BOOL.FALSE;
+                }
+            }
+        }
+
         private struct CpuUtilizationReader
         {
             public long _idleTime;

src/libraries/System.Private.CoreLib/src/System/Threading/PortableThreadPool.WorkerThread.cs

@@ -10,7 +10,7 @@ internal sealed partial class PortableThreadPool
         /// <summary>
         /// The worker thread infastructure for the CLR thread pool.
         /// </summary>
-        private static class WorkerThread
+        private static partial class WorkerThread
         {
             // This value represents an assumption of how much uncommited stack space a worker thread may use in the future.
             // Used in calculations to estimate when to throttle the rate of thread injection to reduce the possibility of
@@ -101,6 +101,12 @@ private static void WorkerThreadStart()
                         }
                     }
 
+                    // The thread cannot exit if it has IO pending, otherwise the IO may be canceled
+                    if (IsIOPending)
+                    {
+                        continue;
+                    }
+
                     threadAdjustmentLock.Acquire();
                     try
                     {