From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 16813 invoked by alias); 24 Jan 2018 19:48:54 -0000 Mailing-List: contact libc-help-help@sourceware.org; run by ezmlm Precedence: bulk List-Subscribe: List-Post: List-Help: , Sender: libc-help-owner@sourceware.org Received: (qmail 16801 invoked by uid 89); 24 Jan 2018 19:48:53 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-2.8 required=5.0 tests=AWL,BAYES_00,RCVD_IN_DNSWL_NONE autolearn=ham version=3.3.2 spammy=his, HContent-Transfer-Encoding:8bit X-HELO: mail-qt0-f174.google.com Received: from mail-qt0-f174.google.com (HELO mail-qt0-f174.google.com) (209.85.216.174) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with ESMTP; Wed, 24 Jan 2018 19:48:52 +0000 Received: by mail-qt0-f174.google.com with SMTP id s3so13407941qtb.10 for ; Wed, 24 Jan 2018 11:48:52 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:organization :message-id:date:user-agent:mime-version:in-reply-to :content-language:content-transfer-encoding; bh=zzrxHNBBRYPoylfQ9GHlzS/7OBGO4RhjYG1/ZtFajws=; b=NCkS/OF/Eg8WGw8mUGj3gEDJLAtwQ9avrwAkGFMcR442YiTFHODda8kl/bm1H9l7pa Y2Pn4vfWVz4aycjNzj0fnrUpXVHeWz0x64rkgs7Ksp0hb8OIfty6DYsuduWkUR7Ofo6Z e/zpTBk7jteoSp6lQZVRjbRgSKbjzWV9nb7Va7xafIElvzIliMn+Dm94d/Mjo1ljAD2r z0F75yKivPs7Yb18k+GgPdxFPjMspDDOIjuU6KbSfrXZws1jhK5uXy8VRyOJM4B+IWJN Zcbv6VK3Yphur/NM+rpLOjuGxO5uwvoi1LovXVKlbcKIDEGCW4wVUZWNGOcTRZu/dITG DyBA== X-Gm-Message-State: AKwxytf/68lo774DX3/oRiNEZ9E3G/UbZCtc2OX3mtd7lfb9rcWpRyCM fNTFFEtg7oRTdRSYCF/43dnAugk2eto= X-Google-Smtp-Source: AH8x227eYoK9BgVO02Y8WMD+CSjTHyBu72mvE2mbN9q+xQ5XQNQvXUImLNcZMGHK0aVtFjqEPl/5Sg== X-Received: by 10.55.119.198 with SMTP id s189mr10182406qkc.88.1516823330604; Wed, 24 Jan 2018 11:48:50 -0800 (PST) Received: from [192.168.1.15] (198.sub-174-215-6.myvzw.com. [174.215.6.198]) by smtp.gmail.com with ESMTPSA id b20sm776397qkj.95.2018.01.24.11.48.48 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 24 Jan 2018 11:48:49 -0800 (PST) Subject: Re: A possible libc/dlmopen/pthreads bug To: Adhemerval Zanella , =?UTF-8?Q?Vivek_Das=c2=a0Mohapatra?= Cc: libc-help@sourceware.org References: <41b64265-397f-1ead-dd79-50052b2d19af@arm.com> <9ff5882f-879f-3069-1ea0-268e2c5e6ac0@linaro.org> <3a0be147-157e-7c78-b35e-556e893f36cb@linaro.org> From: Carlos O'Donell Message-ID: Date: Wed, 24 Jan 2018 19:48:00 -0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.5.0 MIME-Version: 1.0 In-Reply-To: <3a0be147-157e-7c78-b35e-556e893f36cb@linaro.org> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit X-IsSubscribed: yes X-SW-Source: 2018-01/txt/msg00017.txt.bz2 On 01/24/2018 10:27 AM, Adhemerval Zanella wrote: > On 24/01/2018 15:46, Vivek Das Mohapatra wrote: >>> In fact I think Vivek examples of running process with two different libcs >>> are working mainly because the different glibc define and access the shared >>> resources in same manner.  I bet it will break the moment we change some >>> state internal layout or semantic (for instance the __stack_user struct size). >> >> A slight correction - we are deliberately using the _same_ libc to >> avoid exactly that problem - it's that dlmopen as currently implemented >> creates a new mapping of the same libc for the dlmopen namespace. >> >> I also don't need (or expect) complete isolation of the libc cluster: >> If I could, I would share the same mapping of libc & co with the main >> link map. > > Right, you first message gave the impression based on the provided > chart that you expected libc isolation as well. I still think we should > clarify the dlmopen semantics, but we can work on this through bug > reports and issue like this one you brought. > > I think best course of action is still open a bug report with a possible > testcase. I will ping Carlos to check his idea about it, he seemed > interested with previous dlmopen issues. Correct, we need to drive the development forward using specific use cases. -- Cheers, Carlos.