From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <libc-alpha-return-66871-listarch-libc-alpha=sources.redhat.com@sourceware.org>
Received: (qmail 120365 invoked by alias); 2 Feb 2016 13:31:47 -0000
Mailing-List: contact libc-alpha-help@sourceware.org; run by ezmlm
Precedence: bulk
List-Id: <libc-alpha.sourceware.org>
List-Subscribe: <mailto:libc-alpha-subscribe@sourceware.org>
List-Archive: <http://sourceware.org/ml/libc-alpha/>
List-Post: <mailto:libc-alpha@sourceware.org>
List-Help: <mailto:libc-alpha-help@sourceware.org>, <http://sourceware.org/ml/#faqs>
Sender: libc-alpha-owner@sourceware.org
Received: (qmail 120348 invoked by uid 89); 2 Feb 2016 13:31:45 -0000
Authentication-Results: sourceware.org; auth=none
X-Virus-Found: No
X-Spam-SWARE-Status: No, score=-2.6 required=5.0 tests=BAYES_00,RCVD_IN_DNSWL_LOW,SPF_PASS autolearn=ham version=3.3.2 spammy=
X-HELO: mail-qg0-f49.google.com
X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;
        d=1e100.net; s=20130820;
        h=x-gm-message-state:subject:to:references:cc:from:message-id:date
         :user-agent:mime-version:in-reply-to:content-type
         :content-transfer-encoding;
        bh=44eHBD0kuY/LAHwj8UlX7C7YQZwV5F5LaR9GV70ej4E=;
        b=k8wlObS4x3Kxes8NGZMomQEeoC4AKWRP5veZbB7QXFSe0iu5HHUBS2JZk2pJ7I5M+t
         Jh+sEwOshhwlc9JZfiDn4tNJAQqrWSWBcdtH2Juiw9EeOOd3wgjtitTvvk8JVWYJCFtN
         u/hBkPeOx5pwT51iuaLWcvXlynJ4zOZby7bpQL8OKN21qoFOA5N/J2ucjFH5+WFF6Lyl
         /MQAyIpXWls+qQmFFtOw3y2/aTqw67LtBsQEHVprWaEZUGgMOMna7lyBk3fz5+LFv80h
         XVCLyFNtrPjyNlErMGGjxkTmt+RRt166kcXWmYPFfcKj3DTluVBaD5pdd1k51+9uwrhY
         A68Q==
X-Gm-Message-State: AG10YORI2Z4p8yqPorIOFfpLgmGB/yehPvZoxL9f/F8xn6SKcnf6g3JOhiYj7ql4gPGQKnuj
X-Received: by 10.140.102.11 with SMTP id v11mr35714142qge.39.1454419902848;
        Tue, 02 Feb 2016 05:31:42 -0800 (PST)
Subject: Re: [PATCH v2 3/3] posix: New Linux posix_spawn{p} implementation
To: Florian Weimer <fweimer@redhat.com>
References: <1454343665-1706-1-git-send-email-adhemerval.zanella@linaro.org>
 <1454343665-1706-4-git-send-email-adhemerval.zanella@linaro.org>
 <56B0A9B7.6000507@redhat.com>
Cc: libc-alpha@sourceware.org
From: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Message-ID: <56B0AFBB.4050402@linaro.org>
Date: Tue, 02 Feb 2016 13:31:00 -0000
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101
 Thunderbird/38.5.1
MIME-Version: 1.0
In-Reply-To: <56B0A9B7.6000507@redhat.com>
Content-Type: text/plain; charset=windows-1252
Content-Transfer-Encoding: 7bit
X-SW-Source: 2016-02/txt/msg00042.txt.bz2



On 02-02-2016 11:05, Florian Weimer wrote:
> On 02/01/2016 05:21 PM, Adhemerval Zanella wrote:
> 
>> +  new_pid = CLONE (__spawni_child, STACK (stack, stack_size),
>> +		   CLONE_VM | CLONE_VFORK | SIGCHLD, &args);
> 
> Does this set up new per-thread variables?  Otherwise, errno in the
> parent and child will be same and the code still has races.
> 
> Florian
> 

Could you elaborate? In my understanding there is no requirement of
using CLONE_SETTLS to avoid races: CLONE_VFORK will suspend the 
calling process and even with child using the same TLS namespace as
the parent there will be no concurrent access between them.