From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-io0-f199.google.com (mail-io0-f199.google.com [209.85.223.199]) by kanga.kvack.org (Postfix) with ESMTP id A58CB6B0005 for ; Tue, 17 May 2016 06:26:21 -0400 (EDT) Received: by mail-io0-f199.google.com with SMTP id i75so28807379ioa.3 for ; Tue, 17 May 2016 03:26:21 -0700 (PDT) Received: from emea01-db3-obe.outbound.protection.outlook.com (mail-db3on0123.outbound.protection.outlook.com. [157.55.234.123]) by mx.google.com with ESMTPS id j201si941222oib.22.2016.05.17.03.26.20 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Tue, 17 May 2016 03:26:20 -0700 (PDT) Subject: Re: [PATCHv8 resend 2/2] selftest/x86: add mremap vdso test References: <1462886951-23376-1-git-send-email-dsafonov@virtuozzo.com> <1462886951-23376-2-git-send-email-dsafonov@virtuozzo.com> <20160516135442.GA14452@gmail.com> <512f4c9c-7edc-0d12-df96-9708df5f498d@virtuozzo.com> From: Dmitry Safonov Message-ID: <7d74b270-01dd-aab9-8133-249fe9a52767@virtuozzo.com> Date: Tue, 17 May 2016 13:25:04 +0300 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset="utf-8"; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Andy Lutomirski , Ingo Molnar Cc: "linux-kernel@vger.kernel.org" , Ingo Molnar , Thomas Gleixner , "H. Peter Anvin" , X86 ML , Andrew Morton , "linux-mm@kvack.org" , Dmitry Safonov <0x7f454c46@gmail.com>, Shuah Khan , linux-kselftest@vger.kernel.org On 05/16/2016 09:25 PM, Andy Lutomirski wrote: > On Mon, May 16, 2016 at 9:24 AM, Dmitry Safonov wrote: >> On 05/16/2016 04:54 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) >>> >>> >>> Can the segfault be caught and recovered from, to print a proper failure >>> message? >> >> >> Will add segfault handler, thanks. >> > > It may be more complicated that that. Glibc is likely to explode if > this happens, and the headers are sufficiently screwed up that it's > awkward to bypass glibc and call rt_sigaction directly. I have a test > that does the latter, though, so it's at least possible, but I'm > unconvinced it's worth it just for an error message. Oh, I didn't know that, thanks, Andy. I'll leave it as is for simplicity. -- Regards, Dmitry Safonov -- 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