From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751445AbcEVFoP (ORCPT ); Sun, 22 May 2016 01:44:15 -0400 Received: from mail-qg0-f66.google.com ([209.85.192.66]:36362 "EHLO mail-qg0-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751007AbcEVFoO (ORCPT ); Sun, 22 May 2016 01:44:14 -0400 MIME-Version: 1.0 In-Reply-To: <20160521202752.GA31710@gmail.com> References: <1463487232-4377-1-git-send-email-dsafonov@virtuozzo.com> <1463487232-4377-3-git-send-email-dsafonov@virtuozzo.com> <20160520064820.GB29418@gmail.com> <20160521202752.GA31710@gmail.com> From: Dmitry Safonov <0x7f454c46@gmail.com> Date: Sun, 22 May 2016 08:43:53 +0300 Message-ID: Subject: Re: [PATCHv9 2/2] selftest/x86: add mremap vdso test To: Ingo Molnar Cc: Andy Lutomirski , Dmitry Safonov , "linux-kernel@vger.kernel.org" , Ingo Molnar , Thomas Gleixner , "H. Peter Anvin" , X86 ML , Andrew Morton , "linux-mm@kvack.org" , Shuah Khan , linux-kselftest@vger.kernel.org Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 2016-05-21 23:27 GMT+03:00 Ingo Molnar : > > * Andy Lutomirski wrote: > >> On Thu, May 19, 2016 at 11:48 PM, Ingo Molnar wrote: >> > >> > * Dmitry Safonov wrote: >> > >> >> Should print on success: >> >> [root@localhost ~]# ./test_mremap_vdso_32 >> >> AT_SYSINFO_EHDR is 0xf773f000 >> >> [NOTE] Moving vDSO: [f773f000, f7740000] -> [a000000, a001000] >> >> [OK] >> >> Or segfault if landing was bad (before patches): >> >> [root@localhost ~]# ./test_mremap_vdso_32 >> >> AT_SYSINFO_EHDR is 0xf774f000 >> >> [NOTE] Moving vDSO: [f774f000, f7750000] -> [a000000, a001000] >> >> Segmentation fault (core dumped) >> > >> > So I still think that generating potential segfaults is not a proper way to test a >> > new feature. How are we supposed to tell the feature still works? I realize that >> > glibc is a problem here - but that doesn't really change the QA equation: we are >> > adding new kernel code to help essentially a single application out of tens of >> > thousands of applications. >> > >> > At minimum we should have a robust testcase ... >> >> I think it's robust enough. It will print "[OK]" and exit with 0 on >> success and it will crash on failure. The latter should cause make >> run_tests to fail reliably. > > Indeed, you are right - I somehow mis-read it as potentially segfaulting on fixed > kernels as well... > > Will look at applying this after the merge window. Great! Thanks, Ingo - maybe I should have wrote test's patch description better. Thanks again, Andy. From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qk0-f198.google.com (mail-qk0-f198.google.com [209.85.220.198]) by kanga.kvack.org (Postfix) with ESMTP id 614AC6B0005 for ; Sun, 22 May 2016 01:44:14 -0400 (EDT) Received: by mail-qk0-f198.google.com with SMTP id 126so124562940qkl.0 for ; Sat, 21 May 2016 22:44:14 -0700 (PDT) Received: from mail-qg0-x242.google.com (mail-qg0-x242.google.com. [2607:f8b0:400d:c04::242]) by mx.google.com with ESMTPS id d7si25067063qge.124.2016.05.21.22.44.13 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Sat, 21 May 2016 22:44:13 -0700 (PDT) Received: by mail-qg0-x242.google.com with SMTP id 90so12639137qgz.0 for ; Sat, 21 May 2016 22:44:13 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <20160521202752.GA31710@gmail.com> References: <1463487232-4377-1-git-send-email-dsafonov@virtuozzo.com> <1463487232-4377-3-git-send-email-dsafonov@virtuozzo.com> <20160520064820.GB29418@gmail.com> <20160521202752.GA31710@gmail.com> From: Dmitry Safonov <0x7f454c46@gmail.com> Date: Sun, 22 May 2016 08:43:53 +0300 Message-ID: Subject: Re: [PATCHv9 2/2] selftest/x86: add mremap vdso test Content-Type: text/plain; charset=UTF-8 Sender: owner-linux-mm@kvack.org List-ID: To: Ingo Molnar Cc: Andy Lutomirski , Dmitry Safonov , "linux-kernel@vger.kernel.org" , Ingo Molnar , Thomas Gleixner , "H. Peter Anvin" , X86 ML , Andrew Morton , "linux-mm@kvack.org" , Shuah Khan , linux-kselftest@vger.kernel.org 2016-05-21 23:27 GMT+03:00 Ingo Molnar : > > * Andy Lutomirski wrote: > >> On Thu, May 19, 2016 at 11:48 PM, Ingo Molnar wrote: >> > >> > * Dmitry Safonov wrote: >> > >> >> Should print on success: >> >> [root@localhost ~]# ./test_mremap_vdso_32 >> >> AT_SYSINFO_EHDR is 0xf773f000 >> >> [NOTE] Moving vDSO: [f773f000, f7740000] -> [a000000, a001000] >> >> [OK] >> >> Or segfault if landing was bad (before patches): >> >> [root@localhost ~]# ./test_mremap_vdso_32 >> >> AT_SYSINFO_EHDR is 0xf774f000 >> >> [NOTE] Moving vDSO: [f774f000, f7750000] -> [a000000, a001000] >> >> Segmentation fault (core dumped) >> > >> > So I still think that generating potential segfaults is not a proper way to test a >> > new feature. How are we supposed to tell the feature still works? I realize that >> > glibc is a problem here - but that doesn't really change the QA equation: we are >> > adding new kernel code to help essentially a single application out of tens of >> > thousands of applications. >> > >> > At minimum we should have a robust testcase ... >> >> I think it's robust enough. It will print "[OK]" and exit with 0 on >> success and it will crash on failure. The latter should cause make >> run_tests to fail reliably. > > Indeed, you are right - I somehow mis-read it as potentially segfaulting on fixed > kernels as well... > > Will look at applying this after the merge window. Great! Thanks, Ingo - maybe I should have wrote test's patch description better. Thanks again, Andy. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org