c# - 使用 WinDbg 从 minidump 中确定 InnerException 的行号

Question

我正在尝试从转储中追踪 NullReferenceException。 NullReferenceException 不是崩溃异常，而是崩溃异常是带有 InnerException 的 TargetInvocationException，后者是 NullReferenceException。

我将 Windbg 与 SOS 一起使用，我使用命令 analyze -v，这为我提供了 NullReferenceException 的调用堆栈:

EXCEPTION_OBJECT: !pe f6cb150
Exception object: 000000000f6cb150
Exception type:   System.NullReferenceException
Message:          Object reference not set to an instance of an object.
InnerException:   <none>
StackTrace (generated):
SP               IP               Function
000000002CD9D8C0 000007FF01E7C639 MyDll!DoSomething2()+0xe99
000000002CD9DBE0 000007FF01E7B11D MyDll!DoSomething1()+0x43d
000000002CD9DD20 000007FF01E7AB11 MyDll!WorkerDoWork(System.Object, System.ComponentModel.DoWorkEventArgs)+0x51
000000002CD9DD80 000007FEEA68A0F2 System_ni!System.ComponentModel.BackgroundWorker.WorkerThreadStart(System.Object)+0x62

请注意，我得到的方法名称带有字节偏移量，但没有行号。 DoSomething2 是一个大函数，因此 NullReferenceException 发生的位置并不明显。

我尝试按照 Tess Ferrandez 博客中的说明进行操作:

.Net exceptions - Tracking down where in the code the exceptions occurred

但我很早就陷入了尝试使用 !ip2md 和 DoSomething2 的 IP 确定方法 DoSomething2 的方法描述符的地方:7FF01E7C639:

> !ip2md 7FF01E7C639
Failed to request MethodData, not in JIT code range

请注意，!ip2md 命令在发生 TargetInvocationException 的方法的 IP 上成功。

问题:

从这里我可以从哪里开始缩小 DoSomething2 中崩溃的行的范围？请注意，我无法重现崩溃，所以我只有这个(和几个重复的)转储。

附加说明:

• .NET 4.0
• Windbg 版本:6.12.0002.633 AMD64
• 我是 Windbg 的新手:所以信息越多越好

编辑 1

当我没有正确设置符号时，我得到以下信息:

STACK_TEXT:  
00000000`2cd9d8c0 00000000`ffffffff MyDll!Unknown_0xe99+0xe99
00000000`2cd9dbe0 00000000`ffffffff MyDll!Unknown_0x43d+0x43d
00000000`2cd9dd20 00000000`ffffffff MyDll!Unknown_0x51+0x51
00000000`2cd9dd80 00000000`ffffffff system_ni!    System.ComponentModel.BackgroundWorker.WorkerThreadStart+0x62

当我将它设置为指向我的符号服务器并打开 !sym noisy 时，它似乎正确地加载了符号:

0:000> ld MyDll
DBGHELP: C:\Program Files\Debugging Tools for Windows (x64)\MyDll.dll - file not found
SYMSRV:  c:\symbols\MyDll.dll\4F3D6F4B154000\MyDll.dll not found
SYMSRV:  http://msdl.microsoft.com/download/symbols/MyDll.dll/4F3D6F4B154000/MyDll.dll not found
SYMSRV:  \\mysymbolserver\store\Mydll.dll\4F3D6F4B154000\file.ptr
SYMSRV:  MyDll.dl_ from \\mysymbolserver\store: uncompressed
DBGHELP: c:\symbols\MyDll.dll\4F3D6F4B154000\MyDll.dll - OK
DBGENG:  c:\symbols\MyDll.dll\4F3D6F4B154000\MyDll.dll - Mapped image memory
SYMSRV:  c:\symbols\MyDll.pdb\8AFC2BE7529A41289FA9FBCEDB6836161\Mydll.pdb not found
SYMSRV:  http://msdl.microsoft.com/download/symbols/Mydll.pdb/8AFC2BE7529A41289FA9FBCEDB6836161/MyDll.pdb not found
SYMSRV:  \\mysymbolserver\store\MyDll.pdb\8AFC2BE7529A41289FA9FBCEDB6836161\file.ptr
SYMSRV:  MyDll.pd_ from \\mysymbolserver\store: uncompressed
DBGHELP: MyDll - private symbols & lines 
     c:\symbols\MyDll.pdb\8AFC2BE7529A41289FA9FBCEDB6836161\MyDll.pdb
Symbols loaded for MyDll

编辑2

我尝试使用 !name2ee 如下:

0:000> !name2ee MyDll!MyType.DoSomething2
Module:      000007ff004995b8
Assembly:    Autodesk.DataManagement.Client.Framework.Vault.dll
<invalid module token>

所以，运气不好。但后来我似乎几乎有了这个:

0:000> !name2ee MyDll.dll!MyNamespace.MyType
Module:      000007ff004995b8
Assembly:    MyDll.dll
Token:       000000000200008c
MethodTable: 000007ff01b2e258
EEClass:     000007ff01b415e0
Name:        MyNamespace.MyType

0:000> !dumpmt -md 7ff01b2e258
EEClass:      000007ff01b415e0
Module:       000007ff004995b8
Name:         MyNamspace.MyType
mdToken:      000000000200008c
File:         C:\Program Files\MyCompany\MyProduct\Bin\MyDll.dll
BaseSize:        0x30
ComponentSize:   0x0
Slots in VTable: 31
Number of IFaces in IFaceMap: 2
--------------------------------------
MethodDesc Table
           Entry       MethodDesc      JIT Name
000007feeb31a2c0 0000000000000000     NONE 0000000000000000 is not a MethodDesc
000007feeb3689f0 0000000000000000     NONE 0000000000000000 is not a MethodDesc
000007feeb3688c0 0000000000000000     NONE 0000000000000000 is not a MethodDesc
000007feeb353440 0000000000000000     NONE 0000000000000000 is not a MethodDesc
000007ff01b01300 0000000000000000     NONE 0000000000000000 is not a MethodDesc
000007ff01e89140 0000000000000000     NONE 0000000000000000 is not a MethodDesc
000007ff01b9c080 0000000000000000     NONE 0000000000000000 is not a MethodDesc
000007ff01f45f40 0000000000000000     NONE 0000000000000000 is not a MethodDesc
000007ff01a9b358 000007ff01b2e128     NONE MyType.DoSomething3()
000007ff01a9b360 000007ff01b2e130     NONE MyType.DoSomething4()
000007ff01a9b368 000007ff01b2e138     NONE MyType.DoSomething5()
000007ff01e79800 0000000000000000     NONE 0000000000000000 is not a MethodDesc
000007ff020fea80 0000000000000000     NONE 0000000000000000 is not a MethodDesc
000007ff01a9b3b0 000007ff01b2e1b0     NONE MyType.DoSomething6()
000007ff01a9b3b8 000007ff01b2e1b8     NONE MyType.DoSomething7()
000007ff01a9b328 000007ff01b2e0f0     NONE MyType..ctor()
000007ff01b01280 0000000000000000     NONE 0000000000000000 is not a MethodDesc
000007ff01e7a810 0000000000000000     NONE 0000000000000000 is not a MethodDesc
000007ff01e7aac0 0000000000000000     NONE 0000000000000000 is not a MethodDesc
000007ff01e83240 0000000000000000     NONE 0000000000000000 is not a MethodDesc
000007ff01f19520 000007ff01b2e178      JIT MyType.RunWorkerCompleted(System.Object, System.ComponentModel.RunWorkerCompletedEventArgs)
000007ff01e7ace0 0000000000000000      JIT 0000000000000000 is not a MethodDesc
000007ff01e7b7a0 0000000000000000      JIT 0000000000000000 is not a MethodDesc
000007ff01e7b710 0000000000000000      JIT 0000000000000000 is not a MethodDesc
000007ff01e7d2b0 0000000000000000      JIT 0000000000000000 is not a MethodDesc
000007ff01b015f0 0000000000000000      JIT 0000000000000000 is not a MethodDesc
000007ff01b88ce0 0000000000000000      JIT 0000000000000000 is not a MethodDesc
000007ff01a9b3e0 000007ff01b2e200     NONE MyType.DoSomething8()
000007ff01b921e0 0000000000000000     NONE 0000000000000000 is not a MethodDesc
000007ff01b933b0 0000000000000000     NONE 0000000000000000 is not a MethodDesc
000007ff01b93870 0000000000000000     NONE 0000000000000000 is not a MethodDesc

我猜测所有缺失的条目(那些以“不是 MethodDesc”列出的条目)是因为这不是一个完整的小型转储。是吗？

Answer 1

看起来 WinDbg 没有为您的 DLL 选择符号。您可以通过设置符号路径并使用 !sym noisy 来查看它必要时进行故障排除。

我说不出为什么!ip2md在这种情况下不起作用，但还有其他方法可以获取 DoSomething2 的代码.尝试 !name2ee在方法名称上，例如!name2ee *!TypeName.DoSomething2或者你可以像这样通过类型本身获得它 !name2ee *!Namespace.TypeName然后 !dumpmt -md <method table>在您从 !name2ee 获得的方法表上.

获得代码后，!u命令可以向您显示汇编代码的 .NET 注释转储。通过使用异常的偏移量，您可以确定 NullReferenceException 的性质。