A Hang Scenario, Locks and Critical Sections

re: A Hang Scenario, Locks and Critical Sections

Xavier — Wed, 02 Feb 2011 13:28:57 GMT

I have my Page.ProcessRequest hang on me (randomly), but it is not because of a code lock on something that we are doing in code. I am doing a trace and the call to the db and returning of data takes 1 second or so. But for some people it hangs for like 2 minutes (consistently 1:55)

Do you have a tip on how I can debug this?

re: A Hang Scenario, Locks and Critical Sections

Tess1 — Mon, 14 Jun 2010 08:30:27 GMT

Kevin,

its a bit unusual to catch it like that but it means one of two things.

1. the lock is in the middle of transitioning (i.e. someone unlocked and someone else is going to grab the lock) or...

2. rather than using lock, someone is using Monitor.enter and managed to grab the lock without exiting it and the thread exited while the monitor was still held.

Look at what the waiters are doing and see if there is another thread in the middle of leaving the lock

/Tess

re: A Hang Scenario, Locks and Critical Sections

Kevin — Fri, 11 Jun 2010 14:59:50 GMT

What does it mean if the owning thread is 00000000?

Example:

0:000> !syncblk

Index SyncBlock MonitorHeld Recursion Owning Thread Info SyncBlock Owner

62 001ffa3c 36 0 00000000 none 0bc63970 System.RuntimeType+RuntimeTypeCache+MemberInfoCache`1[[System.Reflection.RuntimeMethodInfo, mscorlib]]

Waiting threads: 22 35 36 39 44 45 46 47 50 51 52 53 54 58 59 61 62 63

-----------------------------

Total 89

CCW 2

RCW 0

ComClassFactory 0

Free 22

re: A Hang Scenario, Locks and Critical Sections

Mark — Fri, 23 Jan 2009 13:12:42 GMT

Have you seen Debug Inspector at www.debuginspector.com. It works on managed and unmanaged code and resolves deadlocks where it can.

re: A Hang Scenario, Locks and Critical Sections

Tess1 — Tue, 12 Feb 2008 10:30:31 GMT

Excellent Keith, I'm very happy that it helped:)

re: A Hang Scenario, Locks and Critical Sections

Keith L — Tue, 12 Feb 2008 07:52:38 GMT

Tess, I wanted to thank you for this most excellent set of materials on debugging Deadlocks. Using the tricks you taught in these pages, I was able to debug a deadlock issue that had been plaguing my production website for months.

It's a "slow leak" that took days to repro and I was finally able to trace it down to a bug in the MySql.Data.DLL that I was using to access the Database. Turns out this was a hot issue that had been plaguing many other people and websites for months:

http://bugs.mysql.com/bug.php?id=29289

I wanted to say I would still be clueless if I hadn't learned these nifty tricks from your pages.

Thanks a bundle,

- Keith

Hang caused by GC - XML Deadlock

Noticias externas — Mon, 11 Feb 2008 13:42:48 GMT

In December I blogged about a little tool that i wrote to analyze hangs in dumps , and i showed the following

Hang caused by GC - XML Deadlock

If broken it is, fix it you should — Mon, 11 Feb 2008 12:54:26 GMT

In December I blogged about a little tool that i wrote to analyze hangs in dumps , and i showed the following

Tracking down orphaned critical sections in ASP.NET

ASP.NET Debugging — Fri, 18 Jan 2008 20:57:23 GMT

Recently we have seen quite a few issues where the problem turned out to be an orphaned critical section. 

re: A Hang Scenario, Locks and Critical Sections

Tess1 — Mon, 15 Oct 2007 10:56:07 GMT

LOL:) Thats awesome...