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Mon, 07 Jul 2025 07:59:30 -0700 (PDT) MIME-Version: 1.0 References: <033bf00f1fcf808245ae150346019aa7b997ea11.1751862634.git.alx@kernel.org> In-Reply-To: From: Marco Elver Date: Mon, 7 Jul 2025 16:58:53 +0200 X-Gm-Features: Ac12FXxNc7MVDdqbSkiHg-OPuizBzk24Lc8ThBNq8a8QxrLwekty4YemWnP4YPo Message-ID: Subject: Re: [RFC v3 3/7] mm: Use seprintf() instead of less ergonomic APIs To: Alejandro Colomar Cc: linux-mm@kvack.org, linux-hardening@vger.kernel.org, Kees Cook , Christopher Bazley , shadow <~hallyn/shadow@lists.sr.ht>, linux-kernel@vger.kernel.org, Andrew Morton , kasan-dev@googlegroups.com, Dmitry Vyukov , Alexander Potapenko , Christoph Lameter , David Rientjes , Vlastimil Babka , Roman Gushchin , Harry Yoo , Andrew Clayton , Sven Schnelle , Heiko Carstens , Tvrtko Ursulin , "Huang, Ying" , Lee Schermerhorn , Linus Torvalds , Christophe JAILLET , Hyeonggon Yoo <42.hyeyoo@gmail.com>, Chao Yu Content-Type: text/plain; charset="UTF-8" X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: CCF15C0005 X-Rspam-User: X-Stat-Signature: rux1wpf6tmkqu6xyq8tcjniecaa8oiic X-HE-Tag: 1751900371-890715 X-HE-Meta: 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 arTbCo54 W6JPZy1He/p9ohN7H/Fb0FNHr54lBPyqnaGMvNXaYwKFTiNmJJ3yl0C+4DgteNFi9WsFRMCvUhInck4h+8l/vSrzShUTmqAxADdp7QZeB8p7WLvpkiDAYwtw8CaFhZGAhSL34jY0TLqnFDVYWkwLa3F6rMZdy30qOaayfM0gUQ6SlLXTNyJSNkZSqpZU3LOVtCMKbTNolnZYcNSjPw4wWIN4OPlH+tA/rAXbbnQYKgLeSHnaf3lqiPYxJa+b0sYjnk9TXr2Mwz0q+cJqZIKP4J1eRAnUO+ahNhYe1 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Mon, 7 Jul 2025 at 16:39, Alejandro Colomar wrote: > > Hi Marco, > > On Mon, Jul 07, 2025 at 09:44:09AM +0200, Marco Elver wrote: > > On Mon, 7 Jul 2025 at 07:06, Alejandro Colomar wrote: > > > > > > While doing this, I detected some anomalies in the existing code: > > > > > > mm/kfence/kfence_test.c: > > > > > > - The last call to scnprintf() did increment 'cur', but it's > > > unused after that, so it was dead code. I've removed the dead > > > code in this patch. > > > > That was done to be consistent with the other code for readability, > > and to be clear where the next bytes should be appended (if someone > > decides to append more). There is no runtime dead code, the compiler > > optimizes away the assignment. But I'm indifferent, so removing the > > assignment is fine if you prefer that. > > Yeah, I guessed that might be the reason. I'm fine restoring it if you > prefer it. I tend to use -Wunused-but-set-variable, but if it is not > used here and doesn't trigger, I guess it's fine to keep it. Feel free to make it warning-free, I guess that's useful. > > Did you run the tests? Do they pass? > > I don't know how to run them. I've only built the kernel. If you point > me to instructions on how to run them, I'll do so. Thanks! Should just be CONFIG_KFENCE_KUNIT_TEST=y -- then boot kernel and check that the test reports "ok". Thanks, -- marco