From mboxrd@z Thu Jan 1 00:00:00 1970 From: Davidlohr Bueso Subject: Re: [PATCH v5 0/3] Implement fast refcount overflow protection Date: Wed, 31 May 2017 05:27:32 -0700 Message-ID: <20170531122732.GA24923@linux-80c1.suse> References: <1496180392-98718-1-git-send-email-keescook@chromium.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Return-path: Received: from mx2.suse.de ([195.135.220.15]:57535 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751090AbdEaM1w (ORCPT ); Wed, 31 May 2017 08:27:52 -0400 Content-Disposition: inline In-Reply-To: <1496180392-98718-1-git-send-email-keescook@chromium.org> Sender: linux-arch-owner@vger.kernel.org List-ID: To: Kees Cook Cc: linux-kernel@vger.kernel.org, Christoph Hellwig , Peter Zijlstra , "Eric W. Biederman" , Andrew Morton , Josh Poimboeuf , PaX Team , Jann Horn , Eric Biggers , Elena Reshetova , Hans Liljestrand , David Windsor , Greg KH , Ingo Molnar , Alexey Dobriyan , "Serge E. Hallyn" , arozansk@redhat.com, Manfred Spraul , "axboe@kernel.dk" , James Bottomley On Tue, 30 May 2017, Kees Cook wrote: >A new patch has been added at the start of this series to make the default >refcount_t implementation just use an unchecked atomic_t implementation, >since many kernel subsystems want to be able to opt out of the full >validation, since it includes a small performance overhead. When enabling >CONFIG_REFCOUNT_FULL, the full validation is used. > >The other two patches provide overflow protection on x86 without incurring >a performance penalty. The changelog for patch 3 is reproduced here for >details: To be sure I'm getting this right, after this all archs with the exception of x86 will use the regular atomic_t ("unsecure") flavor, right? Thanks, Davidlohr From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx2.suse.de ([195.135.220.15]:57535 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751090AbdEaM1w (ORCPT ); Wed, 31 May 2017 08:27:52 -0400 Date: Wed, 31 May 2017 05:27:32 -0700 From: Davidlohr Bueso Subject: Re: [PATCH v5 0/3] Implement fast refcount overflow protection Message-ID: <20170531122732.GA24923@linux-80c1.suse> References: <1496180392-98718-1-git-send-email-keescook@chromium.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline In-Reply-To: <1496180392-98718-1-git-send-email-keescook@chromium.org> Sender: linux-arch-owner@vger.kernel.org List-ID: To: Kees Cook Cc: linux-kernel@vger.kernel.org, Christoph Hellwig , Peter Zijlstra , "Eric W. Biederman" , Andrew Morton , Josh Poimboeuf , PaX Team , Jann Horn , Eric Biggers , Elena Reshetova , Hans Liljestrand , David Windsor , Greg KH , Ingo Molnar , Alexey Dobriyan , "Serge E. Hallyn" , arozansk@redhat.com, Manfred Spraul , "axboe@kernel.dk" , James Bottomley , "x86@kernel.org" , Ingo Molnar , Arnd Bergmann , "David S. Miller" , Rik van Riel , linux-arch , "kernel-hardening@lists.openwall.com" Message-ID: <20170531122732.Rqsji3NMCszjbNfCUu2l1qrkWlJye115MpORNvZPihY@z> On Tue, 30 May 2017, Kees Cook wrote: >A new patch has been added at the start of this series to make the default >refcount_t implementation just use an unchecked atomic_t implementation, >since many kernel subsystems want to be able to opt out of the full >validation, since it includes a small performance overhead. When enabling >CONFIG_REFCOUNT_FULL, the full validation is used. > >The other two patches provide overflow protection on x86 without incurring >a performance penalty. The changelog for patch 3 is reproduced here for >details: To be sure I'm getting this right, after this all archs with the exception of x86 will use the regular atomic_t ("unsecure") flavor, right? Thanks, Davidlohr