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Mon, 30 Dec 2024 08:46:48 -0500 (EST) From: Junio C Hamano To: Jeff King Cc: =?utf-8?Q?Ren=C3=A9?= Scharfe , Patrick Steinhardt , git@vger.kernel.org Subject: Re: racy leak sanitizer builds, was Re: [PATCH 0/9] commit-reach: -Wsign-compare follow-ups In-Reply-To: <20241229165715.GA3158370@coredump.intra.peff.net> (Jeff King's message of "Sun, 29 Dec 2024 11:57:15 -0500") References: <20241227-b4-pks-commit-reach-sign-compare-v1-0-07c59c2aa632@pks.im> <20241228190541.GA815586@coredump.intra.peff.net> <20241228192307.GC815586@coredump.intra.peff.net> <965bd864-3ac0-454f-b7bb-f8e0214e9969@web.de> <20241229165715.GA3158370@coredump.intra.peff.net> Date: Mon, 30 Dec 2024 05:46:46 -0800 Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Precedence: bulk X-Mailing-List: git@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain Jeff King writes: > One of the reasons I hadn't sent anything is that I was waffling between > two approaches: > > - implement barriers everywhere and just use them. More work, but we'd > have the tool if we wanted to use it later, and all builds behave > the same. > > - make a "maybe_barrier" interface that might be a noop, and let most > platforms compile without them. They are not needed for correct > operation in most cases, but only to work around a sanitizer problem. > And it is not even a problem that comes up frequently; it is a race > that we occasionally see in CI. So enabling it only for our > linux-leaks CI job would be enough to dull the pain. > > And there is no risk of any portability or run-time issues, because > the code is a noop for most builds. I love when people think before committing to an approach, and after seeing these two cohices, I tend to have slight preference for the latter over the former. The work will not be wasted even if it later turns out that we need a full-blown barrier implementation for other platforms. Thanks.