Subject: Re: Cygwin processes getting stuck on max CPU usage; XP SP2 problem?
From: Brian Dessent <[email-masked]>
To: [email-masked]
Date: Thu, 16 Sep 2004 22:07:04 -0700

Joe Krahn wrote:
> 
> I use SysInternal's Process Explorer a lot. After
> installing XP SP2, if I browse Cygwin processes in
> ProceExp, I can no longer get the list of loaded
> DLLs, and they get stuck at max CPU usage along
> with csrss.exe.
> 
> The CygWin processes continue working OK, but the
> whole system (obviously) gets slowed down.
> 
> I noticed that csrss.exe is new with XP SP2.
> Maybe it's involved in querying process information,
> and does not play well with CygWin?

This is a reported issue and it has to do with the way Process Explorer
works.  It attaches a thread to the target process in order to list the
modules, and cygwin processes don't like this for some reason.  It
started in the early 1.5 days, and is nothing really that new.

If you have symbols installed and you list the threads for the hung
Cygwin process you'll see the stuck one is in a loop in
ntdll.dll!RtlConvertUiListToApiList, as well as a corresponding thread
in csrss.exe (CSRSRV.dll!ValidateMessageString) for each.  The CPU usage
seems to be split equally between them all.

So, it's definitely an interaction between Cygwin and Process Explorer's
grubby little fingers... however no one seems to be interestd in fixing
it so for the time being the solution seems to be "Don't accidently
enable the 'DLLs View' of a cygwin process in ProcExp."

Brian

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