Question

I am writing code implementing some kind of "in-process profiler" component in our multiuser multithread application server. It is basically working perfect - showing stacktraces per thread with some additional information such as CPU utilization for this thread, SQL wait times etc., refreshing every X seconds. I nearly checked-in, but suddenly I noticed in debug session that my application hanged! It happens not all the time, but randomally, hinting on some concurrency problems. After close examination, I ve seen that application hanged during call to "new StackTrace(one_of_my_threads, false)". Here is debugger s stack:

[Managed to Native Transition]  
mscorlib.dll!System.RuntimeType.RuntimeTypeCache.MemberInfoCache<System.Reflection.RuntimeMethodInfo>.AddMethod(System.RuntimeTypeHandle declaringType = {System.RuntimeTypeHandle}, System.RuntimeMethodHandle method, System.RuntimeType.RuntimeTypeCache.CacheType cacheType) + 0x88 bytes   
mscorlib.dll!System.RuntimeType.RuntimeTypeCache.GetMethod(System.RuntimeTypeHandle declaringType, System.RuntimeMethodHandle method) + 0x2d bytes  
mscorlib.dll!System.RuntimeType.GetMethodBase(System.RuntimeTypeHandle reflectedTypeHandle, System.RuntimeMethodHandle methodHandle) + 0xf5 bytes   
mscorlib.dll!System.Diagnostics.StackFrameHelper.GetMethodBase(int i) + 0x4e bytes  
mscorlib.dll!System.Diagnostics.StackTrace.CaptureStackTrace(int iSkip, bool fNeedFileInfo = false, System.Threading.Thread targetThread, System.Exception e = null) + 0xb8 bytes   

mscorlib.dll!System.Diagnostics.StackTrace.StackTrace(System.Threading.Thread targetThread, bool needFileInfo) + 0x18 bytes 

>Almog.Next.Tools.dll!Almog.Next.Services.ThreadWorkUnit.GetStackTrace(System.Threading.Thread th = {System.Threading.Thread}, Almog.Next.Services.StackDetalization details = Simplified) Line 175 + 0x2c bytes    

Almog.Next.Tools.dll!Almog.Next.Services.ThreadWorkUnit.InternalCalculate(Almog.Next.Services.StackDetalization sdetails = Simplified) Line 131 + 0x1b bytes

Almog.Next.Tools.dll!Almog.Next.Services.ThreadWorkUnit.Calculate(Almog.Next.Services.StackDetalization sdetails = Simplified) Line 90 + 0xc bytes

Almog.Next.Tools.dll!Almog.Next.Services.InProcessProfiler.GetThreadWorks(Almog.Next.Services.StackDetalization stackLevel = Simplified) Line 41 + 0xe bytes

Almog.Next.Tools.dll!Almog.Next.CommonControls.ShowWorkloadForm.timer_Tick(object sender = {Interval = 250}, System.EventArgs e = {System.EventArgs}) Line 40 + 0x9 bytes

System.Windows.Forms.dll!System.Windows.Forms.Timer.OnTick(System.EventArgs e) + 0x17 bytes 

System.Windows.Forms.dll!System.Windows.Forms.Timer.TimerNativeWindow.WndProc(ref System.Windows.Forms.Message m) + 0x34 bytes  

System.Windows.Forms.dll!System.Windows.Forms.NativeWindow.Callback(System.IntPtr hWnd, int msg = 275, System.IntPtr wparam, System.IntPtr lparam) + 0x5a bytes 

[Native to Managed Transition]  

[Managed to Native Transition]  

System.Windows.Forms.dll!System.Windows.Forms.Application.ComponentManager.System.Windows.Forms.UnsafeNativeMethods.IMsoComponentManager.FPushMessageLoop(int dwComponentID, int reason = -1, int pvLoopData = 0) + 0x24e bytes 

System.Windows.Forms.dll!System.Windows.Forms.Application.ThreadContext.RunMessageLoopInner(int reason = -1, System.Windows.Forms.ApplicationContext context = {System.Windows.Forms.ApplicationContext}) + 0x177 bytes 

System.Windows.Forms.dll!System.Windows.Forms.Application.ThreadContext.RunMessageLoop(int reason, System.Windows.Forms.ApplicationContext context) + 0x61 bytes    

System.Windows.Forms.dll!System.Windows.Forms.Application.Run(System.Windows.Forms.Form mainForm) + 0x31 bytes  

NextServer.exe!Almog.Next.Server.Program.Main(string[] ParamStr = {string[0]}) Line 24 + 0x1d bytes

我也关注到,在分配新物体(称为“新”)时,其他透镜也受阻。现行例子之一,沿这一法典行:

return new TransactionController(this, transactionMode, isolationLevel);

I believe that every "new" has something to do with MemberInfoCache, but can t figure out what I could do even after looking into AddMethod() s code with Reflector. Please, help! I am completely stuck.

Here is the code reading stacktrace. Nothing unusual, imho: ...

if (th == Thread.CurrentThread)
                throw new NextException("Internal error: it seems the thread {0} once called BeginWork() is the same thread which calls GetThreadWorks() now...", th.ManagedThreadId);
pragma warning disable 612, 618
            th.Suspend();
            var trace = new StackTrace(th, details == StackDetalization.Detailed);
            th.Resume();
pragma warning restore 612, 618
            var sb = new StringBuilder();
            int frameCount = trace.FrameCount;
            for (int i = 0; i < frameCount; i++)
            {

...

预告......

Answer 1

如果你停下来的路子锁,StackTrace正在使用这一锁锁,你将陷入僵局。

Using Thread.Suspend is deprecated for a reason: You basically cannot safely use it. You can only use it if you know exactly what code the suspended thread is running, including any BCL stuff. You cannot know that.

我不知道有解决办法。我猜测,为了抓捕 st物,暂停使用needs?

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