From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 18931 invoked by alias); 30 May 2012 15:54:08 -0000 Received: (qmail 18896 invoked by uid 22791); 30 May 2012 15:53:48 -0000 X-Spam-Check-By: sourceware.org Received: from aquarius.hirmke.de (HELO calimero.vinschen.de) (217.91.18.234) by sourceware.org (qpsmtpd/0.83/v0.83-20-g38e4449) with ESMTP; Wed, 30 May 2012 15:53:34 +0000 Received: by calimero.vinschen.de (Postfix, from userid 500) id 49B712C007B; Wed, 30 May 2012 17:53:32 +0200 (CEST) Date: Wed, 30 May 2012 15:58:00 -0000 From: Corinna Vinschen To: cygwin@cygwin.com Subject: Re: procps and pgrep hang Message-ID: <20120530155332.GC26411@calimero.vinschen.de> Reply-To: cygwin@cygwin.com Mail-Followup-To: cygwin@cygwin.com References: <201205161650.q4GGoiv3000900@localhost.localdomain> <201205170146.q4H1k9AJ001926@localhost.localdomain> <20120517020441.GA10314@ednor.casa.cgf.cx> <201205211640.q4LGeucD023330@localhost.localdomain> <20120523155327.GJ9200@calimero.vinschen.de> <201205301312.q4UDCcIO004057@localhost.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <201205301312.q4UDCcIO004057@localhost.localdomain> User-Agent: Mutt/1.5.21 (2010-09-15) Mailing-List: contact cygwin-help@cygwin.com; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: cygwin-owner@cygwin.com Mail-Followup-To: cygwin@cygwin.com X-SW-Source: 2012-05/txt/msg00632.txt.bz2 On May 30 08:12, Tom Rodman wrote: > On Wed 5/23/12 17:53 +0200 Corinna wrote: > > On May 21 11:40, Tom Rodman wrote: > > > On Wed 5/16/12 22:04 EDT Christopher Faylor wrote: > > > > On Wed, May 16, 2012 at 08:46:09PM -0500, Tom Rodman wrote: > > > > > $ pgrep bash > > > --snip > > > > > $ procps -o pid,args > > > > > PID COMMAND > > > > > 4580 procps -o pid,args > > > > > --note: above command hangs, ended up killing it > > > > > > > > Try a snapshot. > > > > > > Thanks. It seems better, but still hangs, on this box (and 1 other). > > > > > > Examples ran tonight w/20120517 snapshot: > > > > > > http://pastebin.com/xQbtChsJ > > > > Looking into your strace I'm wondering if you really mean hanging in > > the sense of "hanging indefinitely until killed", > > That's what I mean - I have to kill it, it hangs forever. > > > or if you mean it > > hangs for about half a second. Since that's what the strace shows. > > For some of the information about a process under /proc, the requesting > > process has to open a pipe and then, by using a special signal, informs > > that process that it requests information which in turn is send over > > the pipe back to the requester. The timeout for each of the read > > operations on the pipe is restricted to 500ms to avoid indefinite > > hangs. > > > > Unfortunately I can't reproduce this effect, neither on XP nor on W7. > > > > Hmm, puzzeling. I'm wondering though, if this may be a result of using > > message type pipes. Nothing else comes to mind which has changed in > > this piece of code lately. For testing you could set the environment > > variable CYGWIN to "pipe_byte" and try again. > > On my laptop, only the pgrep bug shows up, here is the 'forever hang' > strace w/CYGWIN set to pipe_byte: A signal delivery hangs as if the receiver never reads its signal pipe. I still can't reproduce the problem, though. Can you try to find out which snapshot introduced the problem? Thanks, Corinna -- Corinna Vinschen Please, send mails regarding Cygwin to Cygwin Project Co-Leader cygwin AT cygwin DOT com Red Hat -- Problem reports: http://cygwin.com/problems.html FAQ: http://cygwin.com/faq/ Documentation: http://cygwin.com/docs.html Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple