From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751417AbdJVJ0H (ORCPT ); Sun, 22 Oct 2017 05:26:07 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:42460 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751338AbdJVJ0G (ORCPT ); Sun, 22 Oct 2017 05:26:06 -0400 Subject: Re: [PATCH] objtool: Fix memory leak in decode_instructions() To: Josh Poimboeuf References: <1507798934-18140-1-git-send-email-kamalesh@linux.vnet.ibm.com> <20171012161016.z4ytxmm2rbfiewbl@treble> <1297c97f-844b-0631-311d-8e3742f2f74f@linux.vnet.ibm.com> <20171013050630.cdax2kxj3yqnaton@treble> <8cec1109-8749-0f77-14ca-4bd8e92ebd9d@linux.vnet.ibm.com> <20171019143137.bbte3nwa2pq6uywb@treble> <20171019143226.latzeyhoo3d7dqfo@treble> Cc: linux-kernel@vger.kernel.org, Ingo Molnar From: Kamalesh Babulal Date: Sun, 22 Oct 2017 14:55:56 +0530 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.5.1 MIME-Version: 1.0 In-Reply-To: <20171019143226.latzeyhoo3d7dqfo@treble> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit X-TM-AS-MML: disable x-cbid: 17102209-0008-0000-0000-000004A29791 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 17102209-0009-0000-0000-00001E34F941 Message-Id: X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2017-10-22_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=8.0.1-1707230000 definitions=main-1710220135 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thursday 19 October 2017 08:02 PM, Josh Poimboeuf wrote: > On Thu, Oct 19, 2017 at 09:31:37AM -0500, Josh Poimboeuf wrote: >> On Fri, Oct 13, 2017 at 11:20:58AM +0530, Kamalesh Babulal wrote: >>> On Friday 13 October 2017 10:36 AM, Josh Poimboeuf wrote: >>>> On Fri, Oct 13, 2017 at 10:14:36AM +0530, Kamalesh Babulal wrote: >>>>> On Thursday 12 October 2017 09:40 PM, Josh Poimboeuf wrote: >>>>>> On Thu, Oct 12, 2017 at 02:32:14PM +0530, Kamalesh Babulal wrote: >>>>>>> free the allocated insn before returning, when an error occurs >>>>>>> before adding insn to file->insn_list. >>>>>>> >>>>>>> Signed-off-by: Kamalesh Babulal >>>>>> >>>>>> Any chance you're working on porting objtool to ppc64le? :-) >>>>>> >>>>>> Acked-by: Josh Poimboeuf >>>>>> >>>>> >>>>> Thanks for the review. I have started working on it :) >>>> >>>> Good! Let me know if you have any questions. >>> >>> Thank you, I am sure I will have lots of them. >>> >>>> >>>> I originally wrote objtool with arch-independence in mind, though with >>>> the new "objtool 2.0" rewrite, it unfortunately became more >>>> x86-specific. >>>> >>>> I was hoping to work on making it more arch-independent, and then start >>>> porting it to other arches, but it may be a few months before I have the >>>> time to do so. So any work you want to there would be great. >>>> >>> >>> Sure, will keep that in mind to abstract arch-independent code in to common >>> files and push arch-dependent code into arch/ directory for both >>> ppc64le/x86. >> >> Kamalesh, since you might be working on this soon, here's a bit of a >> brain dump in case it helps. >> >> I have a vague idea for eventually improving objtool, which might make >> arch-independence easier. I wonder if we could use a GCC plugin to add >> annotations in special sections, which are then read by objtool to help >> it understand what's going on in the code. >> >> I suspect the plugins would need to be arch-specific. But then maybe >> that would allow objtool itself to be completely arch-independent. >> Eventually, if we had similar clang plugins, objtool could become >> compiler-independent as well. >> >> Unfortunately I haven't had a chance to think about it any more deeply >> than that. Just something to think about. >> >> Or maybe it makes sense to port objtool to ppc first, before trying to >> abstract the arch-specific parts into plugins. I dunno. >> Thanks for sharing the thoughts on making objtool arch-independent. I have not followed the discussions closely on GCC plugin to add annotations/DWARF data. I will read through the ideas, before commenting on them. >> Also, another idea that has been suggested, is to use DWARF data as >> input to objtool. I have my doubts about that idea, but if it worked, >> that might be another way to help objtool achieve arch-independence. >> >> For a previous discussion of these ideas, see: >> >> https://lkml.kernel.org/r/20170831044209.4hodx2dasad66yab@treble > > Also, any chance you'll be in Prague for the conferences next week? If > so, we could discuss it more in person. > I will not be attending the conference. -- cheers, Kamalesh.