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Tue, 17 Feb 2026 12:55:19 -0800 (PST) MIME-Version: 1.0 References: <20260213123902.3466040-1-arnd@kernel.org> <20260213085842.0654f70a73ec05d88908ec25@linux-foundation.org> <20260213092336.c2b0f2d1be17f1e2e9856f11@linux-foundation.org> In-Reply-To: <20260213092336.c2b0f2d1be17f1e2e9856f11@linux-foundation.org> From: Yuanchu Xie Date: Tue, 17 Feb 2026 14:55:03 -0600 X-Gm-Features: AaiRm52tjFdJFL5QV9uozcplfiuxMj09dq6mSSJMSEz_k17kkZBez8MnH8oZ8wc Message-ID: Subject: Re: [PATCH] mm/vmscan: avoid false-positive -Wuninitialized warning To: Andrew Morton Cc: Arnd Bergmann , Arnd Bergmann , Johannes Weiner , Axel Rasmussen , Wei Xu , "David Hildenbrand (Red Hat)" , Michal Hocko , Qi Zheng , Shakeel Butt , Lorenzo Stoakes , Baolin Wang , Kairui Song , Davidlohr Bueso , Koichiro Den , Jiayuan Chen , Bertrand Wlodarczyk , linux-mm@kvack.org, linux-kernel@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Stat-Signature: w9atnoib8eatt57wnere1m49m7gn971k X-Rspam-User: X-Rspamd-Queue-Id: 21C12100010 X-Rspamd-Server: rspam01 X-HE-Tag: 1771361721-433378 X-HE-Meta: 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 JSDMMW8m tpiPfvNiUVp757W8k3yM8by2fKyQA2wqQUzuSHGmreSVvCpIU2hKSRkHn6YmPmBvXryZajFseQzr4dyovkMWH+cyi5HStyhqful0aif7XWdEJCuKLL/7iolp7AYpig/vtycUiwULd0edBS1mSCYOYLP7s4i0twD6CrUggvPbvTp0gCXuH2lFuBr+VWIJ2LhwGll/xYR8PAaNExeFtQrjR2CHPb33OghHfPplMkZMoRdFIaDlHyi7UC+2m0KFtl3ZHuSgcqLS6pk1vvB6c2ShFDujQzVCfMQfSM/mu2nPn6gBEb8GUZ96bZXOJmifKNIoRu8Pg 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: Hi Andrew and Arnd, On Fri, Feb 13, 2026 at 11:23=E2=80=AFAM Andrew Morton wrote: > > On Fri, 13 Feb 2026 18:07:04 +0100 "Arnd Bergmann" wrote: > > > On Fri, Feb 13, 2026, at 17:58, Andrew Morton wrote: > > > On Fri, 13 Feb 2026 13:38:56 +0100 Arnd Bergmann wr= ote: > > > > > >> From: Arnd Bergmann > > >> > > >> When the -fsanitize=3Dbounds sanitizer is enabled, > > > > > > Is this an option in current kernels? > > > > Yes, this is CONFIG_UBSAN_ARRAY_BOUNDS. The actual warning > > only shows up in some configurations with that, so either there > > is some other dependency, or an element of chance based on gcc > > optimizations. > > OK, I'll put a cc:stable on this, as people will want to compile older > kernels with gcc-16. > > Aiming for upstreaming into 7.1-rc1 unless it's more urgent than I > think. > > > > Seems a large change just to squish a compiler warning. People might > > > prefer a simple > > > > > > - struct ctrl_pos sp, pv; > > > + struct ctrl_pos sp, pv =3D {}; > > > > Right, that would clearly also shut up the warning. > > > > To me this seems less intuitive without an extra comment, > > since read_ctrl_pos() is meant to initialize the entire > > struct, but please pick whichever you find most readable > > here. > > Let's see what the MGLRU maintainers have to say. I went over the various cases of read_ctrl_pos and couldn't find anything wrong (let me know if I'm mistaken), so this seems like a mild compiler bug we're trying to work around. Given it's one single version of gcc, I'm a fan of the simple `struct ctrl_pos sp, pv =3D {};` with a comment. Thanks, Yuanchu