From owner-freebsd-stable@FreeBSD.ORG  Wed Oct 24 02:40:29 2012
Return-Path: <owner-freebsd-stable@FreeBSD.ORG>
Delivered-To: freebsd-stable@freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52])
 by hub.freebsd.org (Postfix) with ESMTP id B81A780B
 for <freebsd-stable@freebsd.org>; Wed, 24 Oct 2012 02:40:29 +0000 (UTC)
 (envelope-from jdc@koitsu.strangled.net)
Received: from qmta13.emeryville.ca.mail.comcast.net
 (qmta13.emeryville.ca.mail.comcast.net [IPv6:2001:558:fe2d:44:76:96:27:243])
 by mx1.freebsd.org (Postfix) with ESMTP id 84B428FC14
 for <freebsd-stable@freebsd.org>; Wed, 24 Oct 2012 02:40:29 +0000 (UTC)
Received: from omta14.emeryville.ca.mail.comcast.net ([76.96.30.60])
 by qmta13.emeryville.ca.mail.comcast.net with comcast
 id Epvk1k0051HpZEsADqgV9r; Wed, 24 Oct 2012 02:40:29 +0000
Received: from koitsu.strangled.net ([67.180.84.87])
 by omta14.emeryville.ca.mail.comcast.net with comcast
 id EqgU1k00F1t3BNj8aqgUud; Wed, 24 Oct 2012 02:40:29 +0000
Received: by icarus.home.lan (Postfix, from userid 1000)
 id 15E9673A1A; Tue, 23 Oct 2012 19:40:28 -0700 (PDT)
Date: Tue, 23 Oct 2012 19:40:28 -0700
From: Jeremy Chadwick <jdc@koitsu.org>
To: Ed Schouten <ed@80386.nl>
Subject: Re: pty/tty or signal strangeness, or grep/bsdgrep bug?
Message-ID: <20121024024028.GA90747@icarus.home.lan>
References: <20121023142703.GA79098@icarus.home.lan>
 <20121023203928.GZ35915@deviant.kiev.zoral.com.ua>
 <CAJOYFBDhDMwgPyWRrzj021eqN=meS3q2FfTi9=5xpVPcXrNxYg@mail.gmail.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <CAJOYFBDhDMwgPyWRrzj021eqN=meS3q2FfTi9=5xpVPcXrNxYg@mail.gmail.com>
User-Agent: Mutt/1.5.21 (2010-09-15)
Cc: Konstantin Belousov <kostikbel@gmail.com>, freebsd-stable@freebsd.org,
 jhb@freebsd.org
X-BeenThere: freebsd-stable@freebsd.org
X-Mailman-Version: 2.1.14
Precedence: list
List-Id: Production branch of FreeBSD source code <freebsd-stable.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/options/freebsd-stable>,
 <mailto:freebsd-stable-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-stable>
List-Post: <mailto:freebsd-stable@freebsd.org>
List-Help: <mailto:freebsd-stable-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-stable>,
 <mailto:freebsd-stable-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Wed, 24 Oct 2012 02:40:30 -0000

On Tue, Oct 23, 2012 at 10:42:47PM +0200, Ed Schouten wrote:
> Hi Kostik,
> 
> 2012/10/23 Konstantin Belousov <kostikbel@gmail.com>:
> > This is reproducable with the cat(1) as well. The telling part is that
> > the backgrounded process stays on the "ttyin" cv. The code for e.g.
> > tty read currently is structured as follows:
> >         check for background process reading from CTTY, send SIGTTYIN
> >         loop {
> >                 sleep waiting for input
> >                 process input
> >         }
> > The problem is that the SIGCONT does not remove the sleeping process from
> > the sleep queue, so the sleep is not interrupted with error. Instead, the
> > process is woken up later when input is available.
> >
> > Old tty code did the recheck for background state inside the loop after
> > the sleep.
> 
> Exactly. Was just debugging this as well and came to the same
> conclusion. Will try to come up with a decent patch tomorrow evening.
> 
> Thanks for reporting the issue!

No problem folks.  Would you like me to file a PR for this so we can
track it/for historical purposes?

-- 
| Jeremy Chadwick                                   jdc@koitsu.org |
| UNIX Systems Administrator                http://jdc.koitsu.org/ |
| Mountain View, CA, US                                            |
| Making life hard for others since 1977.             PGP 4BD6C0CB |