c# - 可以信任 AccessViolationException 的 Stacktrace

Question

在我们的一项服务中抛出 AccessViolationException。我们注册了 AppDomain.CurrentDomain.UnhandledException 并且我们从事件中得到了调用堆栈。该事件在 2 秒内在三个不同的线程上被引发了三次，并且具有完全相同的堆栈。所以一切都应该清楚

另一方面 - Windows 事件日志中的相关日志条目根本不显示任何堆栈。我们的应用程序也使用非托管库，我的猜测是异常是由滥用它们(例如 oci)而不是显示的托管堆栈引起的。

我是否可以相信所报告的堆栈是导致问题的堆栈 - 或者这只是一个有根据的猜测？

System.AccessViolationException: Attempted to read or write protected memory. This is often an indication that other memory is corrupt.
   at System.Linq.EnumerableSorter`2.ComputeKeys(TElement[] elements, Int32 count)
   at System.Linq.EnumerableSorter`1.Sort(TElement[] elements, Int32 count)
   at System.Linq.OrderedEnumerable`1.<GetEnumerator>d__0.MoveNext()
   at System.Linq.Enumerable.<TakeIterator>d__3a`1.MoveNext()
   at System.Data.Services.QueryResultInfo.MoveNext()
   at System.Data.Services.DataService`1.SerializeResponseBody(RequestDescription description, IDataService dataService, IODataResponseMessage responseMessage)
   at System.Data.Services.DataService`1.HandleRequest()
   at System.Data.Services.DataService`1.ProcessRequestForMessage(Stream messageBody)
   at SyncInvokeProcessRequestForMessage(Object , Object[] , Object[] )
   at System.ServiceModel.Dispatcher.SyncMethodInvoker.Invoke(Object instance, Object[] inputs, Object[]& outputs)
   at System.ServiceModel.Dispatcher.DispatchOperationRuntime.InvokeBegin(MessageRpc& rpc)
   at System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage5(MessageRpc& rpc)
   at System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage31(MessageRpc& rpc)
   at System.ServiceModel.Dispatcher.MessageRpc.Process(Boolean isOperationContextSet)
   at System.ServiceModel.Dispatcher.ChannelHandler.DispatchAndReleasePump(RequestContext request, Boolean cleanThread, OperationContext currentOperationContext)
   at System.ServiceModel.Dispatcher.ChannelHandler.HandleRequest(RequestContext request, OperationContext currentOperationContext)
   at System.ServiceModel.Dispatcher.ChannelHandler.AsyncMessagePump(IAsyncResult result)
   at System.Runtime.Fx.AsyncThunk.UnhandledExceptionFrame(IAsyncResult result)
   at System.Runtime.AsyncResult.Complete(Boolean completedSynchronously)
   at System.Runtime.InputQueue`1.AsyncQueueReader.Set(Item item)
   at System.Runtime.InputQueue`1.EnqueueAndDispatch(Item item, Boolean canDispatchOnThisThread)
   at System.Runtime.InputQueue`1.EnqueueAndDispatch(T item, Action dequeuedCallback, Boolean canDispatchOnThisThread)
   at System.ServiceModel.Channels.SingletonChannelAcceptor`3.Enqueue(QueueItemType item, Action dequeuedCallback, Boolean canDispatchOnThisThread)
   at System.ServiceModel.Channels.HttpPipeline.EnqueueMessageAsyncResult.CompleteParseAndEnqueue(IAsyncResult result)
   at System.ServiceModel.Channels.HttpPipeline.EnqueueMessageAsyncResult.HandleParseIncomingMessage(IAsyncResult result)
   at System.Runtime.AsyncResult.SyncContinue(IAsyncResult result)
   at System.ServiceModel.Channels.HttpPipeline.EmptyHttpPipeline.BeginProcessInboundRequest(ReplyChannelAcceptor replyChannelAcceptor, Action dequeuedCallback, AsyncCallback callback, Object state)
   at System.ServiceModel.Channels.HttpChannelListener`1.HttpContextReceivedAsyncResult`1.ProcessHttpContextAsync()
   at System.ServiceModel.Channels.HttpChannelListener`1.BeginHttpContextReceived(HttpRequestContext context, Action acceptorCallback, AsyncCallback callback, Object state)
   at System.ServiceModel.Channels.SharedHttpTransportManager.EnqueueContext(IAsyncResult listenerContextResult)
   at System.ServiceModel.Channels.SharedHttpTransportManager.OnGetContextCore(IAsyncResult listenerContextResult)
   at System.Runtime.Fx.AsyncThunk.UnhandledExceptionFrame(IAsyncResult result)
   at System.Net.LazyAsyncResult.Complete(IntPtr userToken)
   at System.Net.ListenerAsyncResult.IOCompleted(ListenerAsyncResult asyncResult, UInt32 errorCode, UInt32 numBytes)
   at System.Threading._IOCompletionCallback.PerformIOCompletionCallback(UInt32 errorCode, UInt32 numBytes, NativeOverlapped* pOVERLAP)

备注:从 Windows 事件日志中的异常代码猜测，我认为这是一个“真正的”Windows AccessViolationException (0xc000005) 而不是 throw new AccessViolationException (0xe043452)

Answer 1

AccessViolationException 的堆栈跟踪是否指示对访问冲突负责的代码？答案是否。
它仅显示哪个调用检测到访问冲突。随后的调用将失败，实际上整个应用程序将终止，因为 AccessViolationException 不是 catchable by default和 you should not catch it .这意味着内存已被其中一些(并非详尽列表)损坏:

• 对非托管依赖的错误使用
• GCHandle 使用不当
• 错误的不安全代码

您对非托管依赖项的潜在滥用的猜测可能是 AccessViolationException 的根本原因。

请记住，内存损坏不是确定性的:即使发生，运行时也不一定总能检测到。

以下代码是在Console.WriteLine() 中获取AccessViolationException 的方法。但是，它也可能引发 ExecutionEngineException。

    class Program
    {
        static void Main(string[] args)
        {
            AppDomain.CurrentDomain.UnhandledException += OnUnhandledException;
            Thread.CurrentThread.Name = "Main";
            ThreadPool.QueueUserWorkItem(Corrupt, Thread.CurrentThread);
            ThreadPool.QueueUserWorkItem(RunMethod);
            Console.ReadLine();
        }

        private static void OnUnhandledException(object sender, UnhandledExceptionEventArgs e)
        {
            Console.WriteLine(e.ExceptionObject);
        }

        private static void Corrupt(object state)
        {
            unsafe
            {
                var thread = (Thread)state;
                fixed (char* str = thread.Name)
                {
                    char* increment = str;
                    char* decrement = str;
                    while (true)
                    {
                       *(decrement--) = 'f';
                        *(increment++) = 'b';
                        Thread.Sleep(10);
                    }
                }
            }
        }

        [HandleProcessCorruptedStateExceptions ]
        public static void RunMethod(object state)
        {
            try
            {
                while (true)
                {
                    Console.WriteLine("I'm Alive");
                    Thread.Sleep(5000);
                }
            }
            catch (Exception e)
            {
                Console.WriteLine(e);   
            }
        }
    }