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[209.85.208.175]) by smtp.gmail.com with ESMTPSA id b20sm3352976lfi.78.2019.04.23.09.20.06 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 23 Apr 2019 09:20:07 -0700 (PDT) Received: by mail-lj1-f175.google.com with SMTP id v13so1506959ljk.4 for ; Tue, 23 Apr 2019 09:20:06 -0700 (PDT) X-Received: by 2002:a2e:5dd2:: with SMTP id v79mr14738625lje.22.1556036406473; Tue, 23 Apr 2019 09:20:06 -0700 (PDT) MIME-Version: 1.0 References: <20190419215358.WMVFXV3bT%akpm@linux-foundation.org> <20190423082448.GY11158@hirez.programming.kicks-ass.net> In-Reply-To: <20190423082448.GY11158@hirez.programming.kicks-ass.net> From: Linus Torvalds Date: Tue, 23 Apr 2019 09:19:50 -0700 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: mmotm 2019-04-19-14-53 uploaded (objtool) To: Peter Zijlstra Cc: Randy Dunlap , Andrew Morton , Mark Brown , linux-fsdevel , Linux List Kernel Mailing , Linux-MM , linux-next@vger.kernel.org, mhocko@suse.cz, mm-commits@vger.kernel.org, Stephen Rothwell , Josh Poimboeuf , Andy Lutomirski Content-Type: text/plain; charset="UTF-8" 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, Apr 23, 2019 at 1:25 AM Peter Zijlstra wrote: > > Now, we could of course allow this symbol, but I found only the below > was required to make allyesconfig build without issue. > > Andy, Linus? Ack on that patch. Except I think the uaccess.h part should be a separate commit: I think it goes along with 2a418cf3f5f1 ("x86/uaccess: Don't leak the AC flag into __put_user() value evaluation") we did earlier. I think the logic is the same - it's not just the _value_ that can have complex calculations, the address can too (although admittedly that's really not supposed to be common, but you clearly found one case where a complier misfeature made it happen, so...). I also wonder if we should just make "count" be "unsigned long" in do_{strncpy_from,strnlen}_user() too, since we've already done if (unlikely(count <= 0)) return 0; in the caller, so it *is* unsigned by then, and we'd not be mixing signedness when comparing "max/count/res". Linus