使用Windbg在内存转储中查找调用的目标线程
本文关键字:调用 目标 线程 查找 Windbg 内存 转储 使用 | 更新日期: 2023-09-27 17:53:39
背景
一位客户报告C#应用程序挂起。在应用程序挂起时,我有一个内存转储。内存转储显示显示进度表单的主UI线程和正在运行的多个后台线程。其中一个后台线程正在尝试控制。调用回主线程以更新表单。CLR堆栈如下所示:
System.Threading.WaitHandle.WaitOneNative(Microsoft.Win32.SafeHandles.SafeWaitHandle, UInt32, Boolean, Boolean)
System.Threading.WaitHandle.WaitOne(Int64, Boolean)
System.Threading.WaitHandle.WaitOne(Int32, Boolean)
System.Windows.Forms.Control.WaitForWaitHandle(System.Threading.WaitHandle)
System.Windows.Forms.Control.MarshaledInvoke(System.Windows.Forms.Control, System.Delegate, System.Object[], Boolean)
System.Windows.Forms.Control.Invoke(System.Delegate, System.Object[])
profdata.com.Library.frmAsyncExec.SetMessageText(System.String)
profdata.com.Library.frmAsyncExec.SetMessage(System.String, System.String)
profdata.com.Library.frmAsyncExec.DoAsyncProcess(System.Object)
System.Threading.ThreadHelper.ThreadStart_Context(System.Object)
System.Threading.ExecutionContext.runTryCode(System.Object)
System.Runtime.CompilerServices.RuntimeHelpers.ExecuteCodeWithGuaranteedCleanup(TryCode, CleanupCode, System.Object)
System.Threading.ExecutionContext.RunInternal(System.Threading.ExecutionContext, System.Threading.ContextCallback, System.Object)
System.Threading.ExecutionContext.Run(System.Threading.ExecutionContext, System.Threading.ContextCallback, System.Object)
System.Threading.ThreadHelper.ThreadStart(System.Object)
UI线程处于模式循环中,正在等待一条消息:
System.Windows.Forms.UnsafeNativeMethods.WaitMessage()
System.Windows.Forms.Application+ComponentManager.System.Windows.Forms.UnsafeNativeMethods.IMsoComponentManager.FPushMessageLoop(Int32, Int32, Int32)
System.Windows.Forms.Application+ThreadContext.RunMessageLoopInner(Int32, System.Windows.Forms.ApplicationContext)
System.Windows.Forms.Application+ThreadContext.RunMessageLoop(Int32, System.Windows.Forms.ApplicationContext)
System.Windows.Forms.Application.RunDialog(System.Windows.Forms.Form)
System.Windows.Forms.Form.ShowDialog(System.Windows.Forms.IWin32Window)
profdata.com.Library.frmAppletBaseForm.ShowDialog(System.Windows.Forms.IWin32Window)
profdata.com.Library.frmAsyncExec.ExecuteProcess(System.Windows.Forms.IWin32Window)
我验证了消息队列中唯一的消息(我可以看到(是一条绘制消息。消息15对应于WM_PAINT:
0:000> !dso
OS Thread Id: 0x126c (0)
ESP/REG Object Name
ebx 01a688d0 System.Windows.Forms.Application+ThreadContext
esi 01a6eb9c System.Windows.Forms.Application+ComponentManager+ComponentHashtableEntry
edi 1b0c05e0 System.Collections.Hashtable+HashtableEnumerator
0036e244 1b08430c System.Windows.Forms.NativeMethods+MSG[]
0:000> !da 1b08430c
Name: System.Windows.Forms.NativeMethods+MSG[]
MethodTable: 67e0592c
EEClass: 67be89b8
Size: 40(0x28) bytes
Array: Rank 1, Number of elements 1, Type VALUETYPE
Element Methodtable: 67e059dc
0:000> !dumpvc 67e059dc 1b084314
Name: System.Windows.Forms.NativeMethods+MSG
MethodTable 67e059dc
EEClass: 67bbd880
Size: 36(0x24) bytes
(C:'Windows'assembly'GAC_MSIL'System.Windows.Forms'2.0.0.0__b77a5c561934e089'System.Windows.Forms.dll)
Fields:
MT Field Offset Type VT Attr Value Name
691b35f0 4002ba0 0 System.IntPtr 1 instance b02ee hwnd
691b2f74 4002ba1 4 System.Int32 1 instance 15 message
691b35f0 4002ba2 8 System.IntPtr 1 instance 0 wParam
691b35f0 4002ba3 c System.IntPtr 1 instance 0 lParam
691b2f74 4002ba4 10 System.Int32 1 instance 264314085 time
691b2f74 4002ba5 14 System.Int32 1 instance 188 pt_x
691b2f74 4002ba6 18 System.Int32 1 instance 386 pt_y
我知道控制。MarshaledInvoke被实现为已知消息的PostMessage:
private object MarshaledInvoke(Control caller, Delegate method, object[] args, bool synchronous)
{
...
System.Windows.Forms.UnsafeNativeMethods.PostMessage(new HandleRef(this, this.Handle), threadCallbackMessage, IntPtr.Zero, IntPtr.Zero);
...
}
MSDN这样评价PostMessage:
在与创建指定窗口并在不等待的情况下返回的线程以便线程处理消息。
我怀疑这是一个典型的后台线程访问UI对象的情况,已知该对象会导致应用程序挂起。我很清楚这是一件坏事。
由于有多个后台线程,我想确定哪个后台线程搞砸了。
问题
是否可以确定对Control调用的目标线程。使用内存转储中的信息调用?
到目前为止的工作
我得到了后台线程的堆栈对象的转储:
0:000> ~20s
0:020> !dso
OS Thread Id: 0x5d8 (20)
ESP/REG Object Name
ecx 01a2b2d0 System.Runtime.Remoting.Contexts.Context
0c42e49c 1b083e20 System.Threading.ManualResetEvent
0c42e524 01a2006c System.Collections.Hashtable
0c42e560 1b083e38 Microsoft.Win32.SafeHandles.SafeWaitHandle
0c42e5fc 1b044128 System.Windows.Forms.PropertyStore
0c42e608 1b060b68 System.Collections.Queue
0c42e610 1b083de0 System.Windows.Forms.Control+ThreadMethodEntry
0c42e65c 1b043b30 profdata.com.DailyReporting.frmDRAsyncExec
0c42e66c 1b083cb0 System.Object[] (System.Object[])
0c42e670 1b083c90 profdata.com.Library.frmAsyncExec+SetMessageDelegate
0c42e674 1b083cc4 System.Windows.Forms.Control+MultithreadSafeCallScope
0c42e694 1b043b30 profdata.com.DailyReporting.frmDRAsyncExec
我试过浏览ThreadMethodEntry和Context对象,但我不确定我在寻找什么:
0:020> !do 1b083de0
Name: System.Windows.Forms.Control+ThreadMethodEntry
MethodTable: 67e05380
EEClass: 67be8454
Size: 52(0x34) bytes
(C:'Windows'assembly'GAC_MSIL'System.Windows.Forms'2.0.0.0__b77a5c561934e089'System.Windows.Forms.dll)
Fields:
MT Field Offset Type VT Attr Value Name
67dff750 40011b9 4 ...ows.Forms.Control 0 instance 1b043b30 caller
67dff750 40011ba 8 ...ows.Forms.Control 0 instance 1b043b30 marshaler
691b118c 40011bb c System.Delegate 0 instance 1b083c90 method
691844f8 40011bc 10 System.Object[] 0 instance 1b083cb0 args
691b0944 40011bd 14 System.Object 0 instance 00000000 retVal
691b0ebc 40011be 18 System.Exception 0 instance 00000000 exception
691847f4 40011bf 2c System.Boolean 1 instance 1 synchronous
691847f4 40011c0 2d System.Boolean 1 instance 0 isCompleted
69197b54 40011c1 1c ....ManualResetEvent 0 instance 1b083e20 resetEvent
691b0944 40011c2 20 System.Object 0 instance 1b083e14 invokeSyncObject
691ada1c 40011c3 24 ....ExecutionContext 0 instance 1b083cd0 executionContext
691aa00c 40011c4 28 ...ronizationContext 0 instance 00000000 syncContext
0:020> !do 01a2b2d0
Name: System.Runtime.Remoting.Contexts.Context
MethodTable: 691a210c
EEClass: 68fcf620
Size: 60(0x3c) bytes
(C:'Windows'assembly'GAC_32'mscorlib'2.0.0.0__b77a5c561934e089'mscorlib.dll)
Fields:
MT Field Offset Type VT Attr Value Name
691844f8 4001f60 4 System.Object[] 0 instance 01a2b3a0 _ctxProps
691a219c 4001f61 8 ...micPropertyHolder 0 instance 00000000 _dphCtx
691a75b4 4001f62 c ...em.LocalDataStore 0 instance 00000000 _localDataStore
69196f18 4001f63 10 ...ging.IMessageSink 0 instance 00000000 _serverContextChain
69196f18 4001f64 14 ...ging.IMessageSink 0 instance 00000000 _clientContextChain
691b1508 4001f65 18 System.AppDomain 0 instance 01a01298 _appDomain
691844f8 4001f66 1c System.Object[] 0 instance 00000000 _ctxStatics
691b35f0 4001f67 20 System.IntPtr 1 instance 551520 _internalContext
691b2f74 4001f68 24 System.Int32 1 instance 0 _ctxID
691b2f74 4001f69 28 System.Int32 1 instance 3 _ctxFlags
691b2f74 4001f6a 2c System.Int32 1 instance 1 _numCtxProps
691b2f74 4001f6b 30 System.Int32 1 instance 0 _ctxStaticsCurrentBucket
691b2f74 4001f6c 34 System.Int32 1 instance 0 _ctxStaticsFreeIndex
691a219c 4001f6d 654 ...micPropertyHolder 0 shared static _dphGlobal
>> Domain:Value 00557ff8:01a2b068 <<
69189944 4001f6e 658 ...LocalDataStoreMgr 0 shared static _localDataStoreMgr
>> Domain:Value 00557ff8:01a2b07c <<
691b2f74 4001f6f b40 System.Int32 1 shared static _ctxIDCounter
>> Domain:Value 00557ff8:0 <<
或者可能有一种更原生的方法,包括找到窗口句柄与特定线程的关联,但如果是这样,我不知道如何做到这一点。
您需要在ThreadMethodEntry中转储在UI线程上执行的委托(方法字段(。其他成员只是为了让UI线程知道将回调发送到哪个控件,以及在哪个同步上下文中执行回调。
还有一些标志可以检查是否需要调用,如果调用失败,则有一个异常字段,如果是通过invoke调用完成的,则可以将其整理回调用方。你可以放心地忽略那里的其他东西。
有关如何在手头只有委托实例的情况下找到调用了哪个方法的更多信息,请访问此处:http://geekswithblogs.net/akraus1/archive/2012/05/20/149699.aspx
由于您的回调甚至没有执行,因此您也应该查看其他线程。这种神秘的挂起通常与WM_SETTING_CHANGE窗口消息一起发生,其中非UI线程试图调用您的控件(请参阅http://ikriv.com/dev/dotnet/MysteriousHang.html#BeginInvokeDance)。