From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 116771 invoked by alias); 25 Jul 2016 14:28:21 -0000 Mailing-List: contact gdb-patches-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-patches-owner@sourceware.org Received: (qmail 115144 invoked by uid 89); 25 Jul 2016 14:28:21 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-3.2 required=5.0 tests=BAYES_00,RP_MATCHES_RCVD,SPF_HELO_PASS autolearn=ham version=3.3.2 spammy=broad, whom, act X-HELO: mx1.redhat.com Received: from mx1.redhat.com (HELO mx1.redhat.com) (209.132.183.28) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with (AES256-GCM-SHA384 encrypted) ESMTPS; Mon, 25 Jul 2016 14:28:20 +0000 Received: from int-mx10.intmail.prod.int.phx2.redhat.com (int-mx10.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id D44C764D2C; Mon, 25 Jul 2016 14:28:18 +0000 (UTC) Received: from [127.0.0.1] (ovpn01.gateway.prod.ext.ams2.redhat.com [10.39.146.11]) by int-mx10.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id u6PESHIA022043; Mon, 25 Jul 2016 10:28:18 -0400 Subject: Re: [RFC] Set process affinity in test to work around ARM ptrace bug To: Yao Qi References: <1467295036-2816-1-git-send-email-yao.qi@linaro.org> <86a8hxzni8.fsf@gmail.com> Cc: "gdb-patches@sourceware.org" From: Pedro Alves Message-ID: Date: Mon, 25 Jul 2016 14:28:00 -0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.1.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-SW-Source: 2016-07/txt/msg00334.txt.bz2 On 07/25/2016 02:22 PM, Yao Qi wrote: > Ping. Thanks. Hmm. Seeing that the kernel fix was backported to so many stable releases (positively) surprised me. In that case, I question the testsuite workaround a bit harder. If this was a workaround in gdb or gdbserver themselves, then it be more clear to me that the workaround would be going to a broad set of users for whom updating the kernel is not easy. But since this is only for when running the testsuite alone, I could argue that this masks the problem and thus makes it look like gdb works better on an affected system than it really does. I think if I were working on gdb/gdbserver on arm, I'd much prefer if gdb told me my system had a broken ptrace, so I could act on it, rather than masking it off and pretend all is well. How about we make gdb / gdbserver detect bad kernel version, and output a warning to the effect? We already have precedent in nat/linux-ptrace.c. I think we should probably do that regardless of any testsuite workaround. How bad would it be to push for people to update their kernels? >From a testsuite workaround angle, instead of sprinkling set_process_affinity calls around, what if we we added a new proc that would be called at the top of the .exp files: gdb_caching_proc skip_arm_vfp_tests {} { if arm && linux && broken linux versions { return 1 } return 0 } This would skip tests instead of making them pass, but how bad would that be? I assume that people doing gdb development/testing on arm will be able to update their kernels, and will very much want to do that. Thanks, Pedro Alves