From b8a9deab9a60a3aabc1b4fca2e829526ac486d02 Mon Sep 17 00:00:00 2001
From: wangzq <wangzq@gmail.com>
Date: Mon, 12 Mar 2018 09:26:31 -0700
Subject: [PATCH] Fix crashing bug in finalizer

Reproducing code:

      private async void button1_Click(object sender, EventArgs e)
      {
         button1.Enabled = false;
         var file = Path.Combine(AppDomain.CurrentDomain.BaseDirectory, "small.cab");
         var tasks = Enumerable.Range(0, 1000).Select(_ =>
         {
            return Task.Run(() => TestCab(file));
         });
         await Task.WhenAll(tasks);
         button1.Enabled = true;
      }
---
 src/DTF/Libraries/Compression.Cab/CabPacker.cs   | 10 ++++------
 src/DTF/Libraries/Compression.Cab/CabUnpacker.cs | 14 ++++++++------
 2 files changed, 12 insertions(+), 12 deletions(-)

diff --git a/src/DTF/Libraries/Compression.Cab/CabPacker.cs b/src/DTF/Libraries/Compression.Cab/CabPacker.cs
index f263ae2be..7e473f787 100644
--- a/src/DTF/Libraries/Compression.Cab/CabPacker.cs
+++ b/src/DTF/Libraries/Compression.Cab/CabPacker.cs
@@ -424,13 +424,11 @@ protected override void Dispose(bool disposing)
         {
             try
             {
-                if (disposing)
+                // See comment in CabUnpacker.Dispose for more info.
+                if (this.fciHandle != null)
                 {
-                    if (this.fciHandle != null)
-                    {
-                        this.fciHandle.Dispose();
-                        this.fciHandle = null;
-                    }
+                    this.fciHandle.Dispose();
+                    this.fciHandle = null;
                 }
             }
             finally
diff --git a/src/DTF/Libraries/Compression.Cab/CabUnpacker.cs b/src/DTF/Libraries/Compression.Cab/CabUnpacker.cs
index 32b33a0c2..9989efd8c 100644
--- a/src/DTF/Libraries/Compression.Cab/CabUnpacker.cs
+++ b/src/DTF/Libraries/Compression.Cab/CabUnpacker.cs
@@ -324,13 +324,15 @@ protected override void Dispose(bool disposing)
         {
             try
             {
-                if (disposing)
+                // While fdiHandle is a SafeHandle, it will callback to C# method from this instance
+                // when releasing handle, and since finalizers execute in nondeterministic order, if
+                // the handle's finalizer runs after this instance, it will get exception and crash
+                // the process. Therefore we must release this handle regardless of the 'disposing'
+                // flag.
+                if (this.fdiHandle != null)
                 {
-                    if (this.fdiHandle != null)
-                    {
-                        this.fdiHandle.Dispose();
-                        this.fdiHandle = null;
-                    }
+                    this.fdiHandle.Dispose();
+                    this.fdiHandle = null;
                 }
             }
             finally