Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Subject: Re: [PATCH 1/5] glibc: Perform rseq(2) registration at C startup and
 thread creation (v10)
To:     Florian Weimer <fweimer@redhat.com>,
        Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc:     Joseph Myers <joseph@codesourcery.com>,
        Szabolcs Nagy <szabolcs.nagy@arm.com>,
        libc-alpha <libc-alpha@sourceware.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Ben Maurer <bmaurer@fb.com>,
        Peter Zijlstra <peterz@infradead.org>,
        "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
        Boqun Feng <boqun.feng@gmail.com>,
        Will Deacon <will.deacon@arm.com>,
        Dave Watson <davejwatson@fb.com>, Paul Turner <pjt@google.com>,
        Rich Felker <dalias@libc.org>,
        linux-kernel <linux-kernel@vger.kernel.org>,
        linux-api <linux-api@vger.kernel.org>
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 <carlos@redhat.com>
Organization: Red Hat
Message-ID: <c16c9785-7f8c-430b-a4df-a53e47bf1600@redhat.com>
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

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.