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[198.145.64.163]) by smtp.gmail.com with ESMTPSA id v22-20020a636116000000b003c14af505fdsm10713363pgb.21.2022.05.10.08.50.48 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 10 May 2022 08:50:48 -0700 (PDT) Date: Tue, 10 May 2022 08:50:47 -0700 From: Kees Cook To: Christoph Hellwig Cc: "Matthew Wilcox (Oracle)" , "David S. Miller" , Jakub Kicinski , Paolo Abeni , Du Cheng , Christophe JAILLET , Vlastimil Babka , William Kucharski , Arnd Bergmann , Nathan Chancellor , netdev@vger.kernel.org, linux-hardening@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH] niu: Add "overloaded" struct page union member Message-ID: <202205100849.58D2C81@keescook> References: <20220509222334.3544344-1-keescook@chromium.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Authentication-Results: imf16.hostedemail.com; dkim=pass header.d=chromium.org header.s=google header.b=mPax2Elz; spf=pass (imf16.hostedemail.com: domain of keescook@chromium.org designates 209.85.214.180 as permitted sender) smtp.mailfrom=keescook@chromium.org; dmarc=pass (policy=none) header.from=chromium.org X-Rspam-User: X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 603AA180002 X-Stat-Signature: 9gprmdatmzncueawa53czp56y8crkyro X-HE-Tag: 1652197841-921758 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: On Tue, May 10, 2022 at 12:27:53AM -0700, Christoph Hellwig wrote: > On Mon, May 09, 2022 at 03:23:33PM -0700, Kees Cook wrote: > > The randstruct GCC plugin gets upset when it sees struct addresspace > > (which is randomized) being assigned to a struct page (which is not > > randomized): > > Well, the right fix here is to remove this abuse from the driver, not > to legitimize it as part of a "driver" patch touching a core mm header Right, I didn't expect anyone to like the new "overloaded" member. Mainly I'd just like to understand how niu _should_ be fixed. Is using the "private" member the correct thing here? > that doesn't even cc the mm list. Oops, yes, sorry. -- Kees Cook