Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
From:   Florian Weimer <fweimer@redhat.com>
To:     Catalin Marinas <catalin.marinas@arm.com>
Cc:     Szabolcs Nagy <szabolcs.nagy@arm.com>,
        Jeremy Linton <jeremy.linton@arm.com>,
        Mark Brown <broonie@kernel.org>, libc-alpha@sourceware.org,
        Mark Rutland <mark.rutland@arm.com>,
        Will Deacon <will@kernel.org>,
        Kees Cook <keescook@chromium.org>,
        Salvatore Mesoraca <s.mesoraca16@gmail.com>,
        Lennart Poettering <mzxreary@0pointer.de>,
        Topi Miettinen <toiwoton@gmail.com>,
        linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        kernel-hardening@lists.openwall.com,
        linux-hardening@vger.kernel.org
Subject: Re: [PATCH 0/4] aarch64: avoid mprotect(PROT_BTI|PROT_EXEC) [BZ
 #26831]
References: <cover.1604393169.git.szabolcs.nagy@arm.com>
        <20201103173438.GD5545@sirena.org.uk>
        <8c99cc8e-41af-d066-b786-53ac13c2af8a@arm.com>
        <20201104085704.GB24704@arm.com> <20201104144120.GD28902@gaia>
Date:   Wed, 04 Nov 2020 15:45:44 +0100
In-Reply-To: <20201104144120.GD28902@gaia> (Catalin Marinas's message of "Wed,
        4 Nov 2020 14:41:21 +0000")
Message-ID: <87ft5p2naf.fsf@oldenburg2.str.redhat.com>
User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.1 (gnu/linux)
MIME-Version: 1.0
Content-Type: text/plain
Precedence: bulk

* Catalin Marinas:

> Can the dynamic loader mmap() the main exe again while munmap'ing the
> original one? (sorry if it was already discussed)

No, we don't have a descriptor for that.  /proc may not be mounted, and
using the path stored there has a race condition anyway.

Thanks,
Florian
-- 
Red Hat GmbH, https://de.redhat.com/ , Registered seat: Grasbrunn,
Commercial register: Amtsgericht Muenchen, HRB 153243,
Managing Directors: Charles Cachera, Brian Klemm, Laurie Krebs, Michael O'Neill