From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754765AbeCGPMK (ORCPT ); Wed, 7 Mar 2018 10:12:10 -0500 Received: from mailout.easymail.ca ([64.68.200.34]:50913 "EHLO mailout.easymail.ca" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754645AbeCGPMH (ORCPT ); Wed, 7 Mar 2018 10:12:07 -0500 Reply-To: shuah@kernel.org Subject: Re: [PATCH] selftests/size: rework to use main instead of _start To: Anders Roxell , tbird20d@gmail.com Cc: linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org, Shuah Khan , Shuah Khan References: <20180307130725.8267-1-anders.roxell@linaro.org> From: Shuah Khan Message-ID: <613a519a-9c2b-fb11-ecb9-f3c464d0af43@kernel.org> Date: Wed, 7 Mar 2018 08:11:57 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.6.0 MIME-Version: 1.0 In-Reply-To: <20180307130725.8267-1-anders.roxell@linaro.org> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 03/07/2018 06:07 AM, Anders Roxell wrote: > In a -ffreestanding environment without glibc, we shouldn't be able to > call either getenv or printf. It seems that printf() happens to work > fine, but it ends up using the glibc getenv(), which doesn't work unless > we call the glibc _start() function first. > Using _start() was originally meant as an optimization to reduce the > memory consumption of the test program itself, in order to get a more > accurate representation of the available RAM at system boot time. > However, it causes more problems than it helps, especially when run from > a shell script that also consumes some memory. > > get_size[2838]: segfault at ffffffffffffffd0 ip 000000000040538b > sp 00007ffc41980668 error 5 in get_size[400000+b0000] > audit: type=1701 audit(1521532923.838:4): auid=0 uid=0 gid=0 ses=2 > subj=kernel pid=2838 comm=\"get_size\" > exe=\"/opt/kselftests/next/size/get_size\" sig=11 res=1 > get_size[2840]: segfault at ffffffffffffffd0 ip 000000000040538b > sp 00007ffdace9b378 error 5 in get_size[400000+b0000] > audit: type=1701 audit(1521532932.057:5): auid=0 uid=0 gid=0 ses=2 > subj=kernel pid=2840 comm=\"get_size\" > exe=\"/opt/kselftests/next/size/get_size\" sig=11 res=1 > > Rework to get_size test to use main (and printf) instead of _start. All > other seftest tests uses main and not _start. > > Fixes: 0081901af95f ("selftests: size call ksft_print_header() to print TAP header") > Signed-off-by: Anders Roxell Andres, Thanks for finding and reporting the problem. This patch is in linux-kselftest next for 4.17-rc1. I would rather revert the patch than fix it a this time. I knew there was a reason why Tim didn't use printf() in the first, I couldn't remember. I won't be sending 0081901af95f ("selftests: size call ksft_print_header() to print TAP header") for inclusion into 4.17-rc1 thanks, -- Shuah