From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-lj1-f194.google.com ([209.85.208.194]:34720 "EHLO mail-lj1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725824AbeJLF30 (ORCPT ); Fri, 12 Oct 2018 01:29:26 -0400 Date: Fri, 12 Oct 2018 01:00:09 +0300 From: Cyrill Gorcunov To: Alexey Dobriyan Cc: Rafael David Tinoco , linux-kselftest@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, akpm@linux-foundation.org, shuah@kernel.org Subject: Re: [PATCH] proc: fix proc-self-map-files selftest for arm Message-ID: <20181011220009.GF2401@uranus.lan> References: <20181011184359.15627-1-rafael.tinoco@linaro.org> <20181011205601.GA32757@avx2> <20181011210256.GE2401@uranus.lan> <20181011213006.GA13485@avx2> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181011213006.GA13485@avx2> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: On Fri, Oct 12, 2018 at 12:30:06AM +0300, Alexey Dobriyan wrote: > On Fri, Oct 12, 2018 at 12:02:56AM +0300, Cyrill Gorcunov wrote: > > On Thu, Oct 11, 2018 at 11:56:01PM +0300, Alexey Dobriyan wrote: > > > > > > As the comment in the beginning says this test is specifically for addresss 0. > > > Maybe it should be ifdeffed with __arm__ then. > > > > Is there some other reason than allocating non-mergable VMA? > > IIRC the reason is to test address 0 as it is effectively banned > for userspace so if it will be broken, it will be broken silently > for a long time. This is rather a side effect of the test because the primary reason was to check procfs numbers conversion, right? Don't get me wrong, I don't mind about __arm__ define or similar, this is fine for one architecture, but if there comes more we will get a number of #ifdefs which is unrelated to procfs numeric routines at all. > As for "unmergeable" libc here doesn't map /dev/zero. I know how to > avoid even theoretical breakage by creating binaries by hand but it > will be probably too much. Sure.