Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932279AbbKCSVm (ORCPT ); Tue, 3 Nov 2015 13:21:42 -0500 Received: from mail-pa0-f50.google.com ([209.85.220.50]:33779 "EHLO mail-pa0-f50.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753996AbbKCSVj (ORCPT ); Tue, 3 Nov 2015 13:21:39 -0500 Subject: Re: [PATCH 1/2] mm: mmap: Add new /proc tunable for mmap_base ASLR. To: "Eric W. Biederman" References: <1446067520-31806-1-git-send-email-dcashman@android.com> <871tcewoso.fsf@x220.int.ebiederm.org> <87oafiuys0.fsf@x220.int.ebiederm.org> <56329880.4080103@android.com> <87k2q1tmna.fsf@x220.int.ebiederm.org> Cc: Jeffrey Vander Stoep , linux-kernel@vger.kernel.org, linux@arm.linux.org.uk, Andrew Morton , Kees Cook , mingo@kernel.org, linux-arm-kernel@lists.infradead.org, Jonathan Corbet , dzickus@redhat.com, xypron.glpk@gmx.de, jpoimboe@redhat.com, kirill.shutemov@linux.intel.com, n-horiguchi@ah.jp.nec.com, aarcange@redhat.com, Mel Gorman , tglx@linutronix.de, rientjes@google.com, linux-mm@kvack.org, linux-doc@vger.kernel.org, Mark Salyzyn , Nick Kralevich , dcashman From: Daniel Cashman Message-ID: <5638FB2F.8040107@android.com> Date: Tue, 3 Nov 2015 10:21:35 -0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.3.0 MIME-Version: 1.0 In-Reply-To: <87k2q1tmna.fsf@x220.int.ebiederm.org> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2344 Lines: 52 On 11/01/2015 01:50 PM, Eric W. Biederman wrote: > Daniel Cashman writes: > >> On 10/28/2015 08:41 PM, Eric W. Biederman wrote: >>> Dan Cashman writes: >>> >>>>>> This all would be much cleaner if the arm architecture code were just to >>>>>> register the sysctl itself. >>>>>> >>>>>> As it sits this looks like a patchset that does not meaninfully bisect, >>>>>> and would result in code that is hard to trace and understand. >>>>> >>>>> I believe the intent is to follow up with more architecture specific >>>>> patches to allow each architecture to define the number of bits to use >>>> >>>> Yes. I included these patches together because they provide mutual >>>> context, but each has a different outcome and they could be taken >>>> separately. >>> >>> They can not. The first patch is incomplete by itself. >> >> Could you be more specific in what makes the first patch incomplete? Is >> it because it is essentially a no-op without additional architecture >> changes (e.g. the second patch) or is it specifically because it >> introduces and uses the three "mmap_rnd_bits*" variables without >> defining them? If the former, I'd like to avoid combining the general >> procfs change with any architecture-specific one(s). If the latter, I >> hope the proposal below addresses that. > > A bit of both. The fact that the code can not compile in the first > patch because of missing variables is distressing. Having the arch > specific code as a separate patch is fine, but they need to remain in > the same patchset. > The first patch would compile as long as CONFIG_ARCH_MMAP_RND_BITS were not defined without also defining the missing variables. I actually viewed this as a safeguard against attempting to use those variables without architecture support, but am ok with changing it. I've gone ahead and submitted [PATCH v2] which aims to reduce duplication in the arch-specific config files and concerning those variables. The only caveat is that now the second patch depends on the first, whereas before it did not. Thank You, Dan -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/