From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754566AbcEPSZl (ORCPT ); Mon, 16 May 2016 14:25:41 -0400 Received: from mail-oi0-f47.google.com ([209.85.218.47]:34573 "EHLO mail-oi0-f47.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754517AbcEPSZc (ORCPT ); Mon, 16 May 2016 14:25:32 -0400 MIME-Version: 1.0 In-Reply-To: <512f4c9c-7edc-0d12-df96-9708df5f498d@virtuozzo.com> 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: Andy Lutomirski Date: Mon, 16 May 2016 11:25:12 -0700 Message-ID: Subject: Re: [PATCHv8 resend 2/2] selftest/x86: add mremap vdso test To: Dmitry Safonov Cc: Ingo Molnar , "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 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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. -- Andy Lutomirski AMA Capital Management, LLC