From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753271AbcKIJVi (ORCPT ); Wed, 9 Nov 2016 04:21:38 -0500 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:53583 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752802AbcKIJVc (ORCPT ); Wed, 9 Nov 2016 04:21:32 -0500 Subject: Re: [PATCH] gcov: support GCC 7.1 To: =?UTF-8?Q?Martin_Li=c5=a1ka?= References: <8c4084fa-3885-29fe-5fc4-0d4ca199c785@suse.cz> From: Peter Oberparleiter Cc: lkml Date: Wed, 9 Nov 2016 10:21:29 +0100 MIME-Version: 1.0 In-Reply-To: <8c4084fa-3885-29fe-5fc4-0d4ca199c785@suse.cz> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 16110909-0040-0000-0000-000003027833 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 16110909-0041-0000-0000-00001DCD71D3 Message-Id: <85a7ed9a-4915-49d9-f17b-888b838107c6@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2016-11-09_03:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=1 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1609300000 definitions=main-1611090177 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 31.10.2016 10:35, Martin Liška wrote: > Starting from GCC 7.1, __gcov_exit is a new symbol expected > to be implemented in a profiling runtime. I tested your patch with kernel 4.9-rc4 compiled with GCC 7.0.0 20161107 (experimental) and validated that it fixes the build error due to a missing __gcov_exit symbol. An attempt to read from one of the .gcda files generated by a kernel compiled this way resulted in a crash though. It appears that the number of GCOV_COUNTERS has changed again for GCC 7.x and must be adjusted in the kernel as well. Could you add that to your patch as well? Given that GCC 7.1 has not yet been released, I'm wondering if it is safe to program against interfaces that have not yet been fully finalized. Can you provide an indication on whether these gcov-related aspects of GCC might still be changed until release? As a side note, please post your patches inline instead of as attachment as that helps quoting them in replies. See also linux/Documentation/SubmittingPatches. -- Peter Oberparleiter Linux on z Systems Development - IBM Germany