Comment Feed for Channel 9 - Understanding handle leaks and how to use !htrace to find them http://ecn.channel9.msdn.com/o9/previewImages/100/257621_100x75.jpg Channel 9 - Understanding handle leaks and how to use !htrace to find them Hello, my name is Jeff Dailey, I’m an Escalation Engineer for the Global Escalation Services Platforms team.   I’d like to show you how to debug and find leaking handles within your application or other process.  We can do this with the !htrace command in windbg .  Windbg is the Microsoft Windows Debugger most of us use in GES/CPR  for debugging.      Handles are a value we use in user mode, that when passed to a call that transitions to kernel, are used as an offset in your handle table to reference kernel mode objects.  Kernel mode objects are generally allocated from pool.   If you are having pool consumption problems and seeing errors like 2020 or 2019’s reported there is a good chance you may have a handle leak associated with them.  This is generally due to not doing a CloseHandle() on the handle when you have finished using it.   The following is the sample source for a handle leak that we will be debugging in our demo video.   // leakyhandles.cpp : Defines the entry point for the console application. //   #include "stdafx.h" #include <windows.h>     void fun1(void); void fun2(void); void fun3(void); void fun4(void);   int main(int argc, char* argv[]) {       while(1)       {             fun1();             fun2();             Sleep(100);       }       return 0; }   void fun1(void) {       fun3(); }   void fun2(void) {       fun4();   } void fun3(void) {       HANDLE hEvent;         hEvent = CreateEvent(NULL,TRUE,TRUE,NULL);       CloseHandle(hEvent); } void fun4(void) {     HANDLE hEvent2;         hEvent2 = CreateEvent(NULL,TRUE,TRUE,NULL); }   Thank you. Jeff Dailey Escalation Engineer (Platforms core team) en Thu, 23 May 2013 15:25:44 GMT Thu, 23 May 2013 15:25:44 GMT Rev9 Re: Understanding handle leaks and how to use !htrace to find them Seems like the CHM which you have shown comes with MS confidential (private) version of windbg...

(though there is not much difference in the page thats shown!)

But thanks for taking initiative and start giving nice small tutorials on debugging with windbg..

posted by jigarmehtamscit

]]> http://channel9.msdn.com/Blogs/jeff_dailey/Understanding-handle-leaks-and-how-to-use-htrace-to-find-them#c633254043610000000 Fri, 14 Sep 2007 22:06:01 GMT http://channel9.msdn.com/Blogs/jeff_dailey/Understanding-handle-leaks-and-how-to-use-htrace-to-find-them#c633254043610000000 jigarmehtamscit Re: Understanding handle leaks and how to use !htrace to find them

posted by dcook

]]> http://channel9.msdn.com/Blogs/jeff_dailey/Understanding-handle-leaks-and-how-to-use-htrace-to-find-them#c633254903940000000 Sat, 15 Sep 2007 21:59:54 GMT http://channel9.msdn.com/Blogs/jeff_dailey/Understanding-handle-leaks-and-how-to-use-htrace-to-find-them#c633254903940000000 dcook Re: Understanding handle leaks and how to use !htrace to find them
Hope to see more of those trainings in future...

Cheers,
Volker

http://www.voneinem-windbg.blogspot.com/

posted by vve

]]> http://channel9.msdn.com/Blogs/jeff_dailey/Understanding-handle-leaks-and-how-to-use-htrace-to-find-them#c633256388280000000 Mon, 17 Sep 2007 15:13:48 GMT http://channel9.msdn.com/Blogs/jeff_dailey/Understanding-handle-leaks-and-how-to-use-htrace-to-find-them#c633256388280000000 vve Re: Understanding handle leaks and how to use !htrace to find them i have tried for several times to watch this video, but every time after it played about 1 or 2 mins, it just stopped...

i have no way to finish watching the video, is there anyway i can do about it?? my bandwidth is 12mb download/1mb upload, so it's not a bandwidth problem.

is there anyway i can download the video or just think a way to help me be able to watch it....

posted by MythTW

]]> http://channel9.msdn.com/Blogs/jeff_dailey/Understanding-handle-leaks-and-how-to-use-htrace-to-find-them#c633272695620000000 Sat, 06 Oct 2007 12:12:42 GMT http://channel9.msdn.com/Blogs/jeff_dailey/Understanding-handle-leaks-and-how-to-use-htrace-to-find-them#c633272695620000000 MythTW Re: Understanding handle leaks and how to use !htrace to find them Going to play with this method on my machine now...
thanks for the tutorial..

posted by MythTW

]]> http://channel9.msdn.com/Blogs/jeff_dailey/Understanding-handle-leaks-and-how-to-use-htrace-to-find-them#c633273446070000000 Sun, 07 Oct 2007 09:03:27 GMT http://channel9.msdn.com/Blogs/jeff_dailey/Understanding-handle-leaks-and-how-to-use-htrace-to-find-them#c633273446070000000 MythTW Re: Understanding handle leaks and how to use !htrace to find them I am alos not able to watch the video ....which tool helped to donwload wmv...?

posted by sang

]]> http://channel9.msdn.com/Blogs/jeff_dailey/Understanding-handle-leaks-and-how-to-use-htrace-to-find-them#c633807306420000000 Tue, 16 Jun 2009 06:30:42 GMT http://channel9.msdn.com/Blogs/jeff_dailey/Understanding-handle-leaks-and-how-to-use-htrace-to-find-them#c633807306420000000 sang Re: Understanding handle leaks and how to use !htrace to find them  

You can click on the "Formats:" drop-down and in the list, right-click the WMV and choose "Save-As". At least that worked for me. This was the direct link from that:

http://mschnlnine.vo.llnwd.net/d1/ch9/1/2/6/7/5/2/341851_leakyhandles.wmv

posted by c0decafe

]]> http://channel9.msdn.com/Blogs/jeff_dailey/Understanding-handle-leaks-and-how-to-use-htrace-to-find-them#c633837925590000000 Tue, 21 Jul 2009 17:02:39 GMT http://channel9.msdn.com/Blogs/jeff_dailey/Understanding-handle-leaks-and-how-to-use-htrace-to-find-them#c633837925590000000 c0decafe Re: Understanding handle leaks and how to use !htrace to find them posted by anonymous

]]> http://channel9.msdn.com/Blogs/jeff_dailey/Understanding-handle-leaks-and-how-to-use-htrace-to-find-them#c634256567690000000 Thu, 18 Nov 2010 05:59:29 GMT http://channel9.msdn.com/Blogs/jeff_dailey/Understanding-handle-leaks-and-how-to-use-htrace-to-find-them#c634256567690000000 anonymous