From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9856DC31E40 for ; Mon, 10 Jun 2019 14:43:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7B68E2085A for ; Mon, 10 Jun 2019 14:43:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390938AbfFJOn5 (ORCPT ); Mon, 10 Jun 2019 10:43:57 -0400 Received: from mail-vs1-f68.google.com ([209.85.217.68]:42211 "EHLO mail-vs1-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389075AbfFJOn4 (ORCPT ); Mon, 10 Jun 2019 10:43:56 -0400 Received: by mail-vs1-f68.google.com with SMTP id 190so1863612vsf.9 for ; Mon, 10 Jun 2019 07:43:56 -0700 (PDT) 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=rzTYIiPqSMbaB247OwcvP22Dn5ctSBRMkQLSP6g63TE=; b=SJtb1wy/Row31R2fyWz4/64ltn+79CBmUH7O6fyuyrazBXix902JVnY0wC2fE5+uhj xmhwNoTKbAFrvXxiZaIT6CDwjRa+f6I5l1cMXoAGg98mcrE0cE0WJyo8g2HlFKUumMJX IrEVY9XvYTYn9Ad8XxtKQIxs66yDfDufMEcWz3aJ+O/+4FA2jNkTr65pquWjU+MfOui9 uSgWEr4Z/jG84+vNScbEMZIYOUoY5U0Eo2CZm0hBFKlHYGtggUWfAse68Jv0aXVlb+gS r3pewzPhqZsFdxi72A8MTRQHj3RkYlAtcz0L4DymsxFqTyvbLT+IrPageUclHlbOKY6q En/A== X-Gm-Message-State: APjAAAW+9g3R/ZMU7X/a+7IQqXUEHFBldryyM/+/0jxf8MpKn8pMBN8B LTyFfIL8uCGyUyk0fgSwZZ7q6w== X-Google-Smtp-Source: APXvYqzj3JGOnWo66BHBaY1lDSf86H5ulmKxbipFqXHDa+gBq4fz7JnKtO1dzGP3noNi8L0rfXRlQw== X-Received: by 2002:a67:ed04:: with SMTP id l4mr17840852vsp.179.1560177835906; Mon, 10 Jun 2019 07:43:55 -0700 (PDT) Received: from [192.168.8.101] ([67.69.69.230]) by smtp.gmail.com with ESMTPSA id a123sm3187094vka.22.2019.06.10.07.43.51 (version=TLS1_3 cipher=AEAD-AES128-GCM-SHA256 bits=128/128); Mon, 10 Jun 2019 07:43:54 -0700 (PDT) Subject: Re: [PATCH 1/5] glibc: Perform rseq(2) registration at C startup and thread creation (v10) To: Florian Weimer , Mathieu Desnoyers Cc: Joseph Myers , Szabolcs Nagy , libc-alpha , Thomas Gleixner , Ben Maurer , Peter Zijlstra , "Paul E. McKenney" , Boqun Feng , Will Deacon , Dave Watson , Paul Turner , Rich Felker , linux-kernel , linux-api References: <20190503184219.19266-1-mathieu.desnoyers@efficios.com> <140718133.18261.1559144710554.JavaMail.zimbra@efficios.com> <2022553041.20966.1559249801435.JavaMail.zimbra@efficios.com> <875zprm4jo.fsf@oldenburg2.str.redhat.com> <732661684.21584.1559314109886.JavaMail.zimbra@efficios.com> <87muj2k4ov.fsf@oldenburg2.str.redhat.com> <1528929896.22217.1559326257155.JavaMail.zimbra@efficios.com> <87o93d4lqb.fsf@oldenburg2.str.redhat.com> <117220011.27079.1559663870037.JavaMail.zimbra@efficios.com> <87wohzorj0.fsf@oldenburg2.str.redhat.com> From: Carlos O'Donell Organization: Red Hat Message-ID: Date: Mon, 10 Jun 2019 10:43:50 -0400 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.7.0 MIME-Version: 1.0 In-Reply-To: <87wohzorj0.fsf@oldenburg2.str.redhat.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 6/6/19 7:57 AM, Florian Weimer wrote: > Let me ask the key question again: Does it matter if code observes the > rseq area first without kernel support, and then with kernel support? > If we don't expect any problems immediately, we do not need to worry > much about the constructor ordering right now. I expect that over time, > fixing this properly will become easier. I just wanted to chime in and say that splitting this into: * Ownership (__rseq_handled) * Initialization (__rseq_abi) Makes sense to me. I agree we need an answer to this question of ownership but not yet initialized, to owned and initialized. I like the idea of having __rseq_handled in ld.so. -- Cheers, Carlos.