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From: "Dave Korn" <dave DOT korn AT artimi DOT com>
To: <cygwin AT cygwin DOT com>
Subject: RE: cygwin-1.dll long-time bug
Date: Tue, 18 Apr 2006 17:23:24 +0100
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On 18 April 2006 10:12, burning shadow wrote:

> There is a bug in all cygwin processes which leads to 100% CPU usage
> and locking another processes. For example, there was a windows update
> (installed automatically using Automatic Updates) from Microsoft,
> which couldn't be installed until all cygwin processes are stopped. It
> happens with some utilities which somehow work with process
> information. For example, this happens if I try to see threads tab of
> cygwin process in Process Explorer. I thought it was a Process
> Explorer's bug, but the same happens with another utilities, and even
> with windows updates.

  It's not a bug, it's a feature :)

  Actually, it's an unexpected interaction, quite possibly a side-effect of injecting MSVCRT-based code into a cygwin-based thread and having them fight over ownership of various TLS slots.  It's very hard to track down though because debugging the csrss subsystem whilst using a debugger based on the win32 gui can be just a bit tricky..... :)

  Ah, I just found something out.  The function that's causing all the trouble is ntdll!RtlpQueryProcessDebugInformationRemote; that's somehow going into a massive task-switching thrash against csrss and never completing.  Second time you bring up the thread monitor you get a second thread doing the same thing.  Hey, I've got something to work with now... I'll keep the list posted.

    cheers,
      DaveK
-- 
Can't think of a witty .sigline today....


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