From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753677AbbIAMtH (ORCPT ); Tue, 1 Sep 2015 08:49:07 -0400 Received: from szxga03-in.huawei.com ([119.145.14.66]:36004 "EHLO szxga03-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752611AbbIAMtF (ORCPT ); Tue, 1 Sep 2015 08:49:05 -0400 Message-ID: <55E59DBA.1000709@huawei.com> Date: Tue, 1 Sep 2015 20:44:42 +0800 From: "Wangnan (F)" User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:31.0) Gecko/20100101 Thunderbird/31.6.0 MIME-Version: 1.0 To: Jiri Olsa , Arnaldo Carvalho de Melo CC: Jiri Olsa , , , , , , Masami Hiramatsu , Namhyung Kim Subject: Re: [PATCH 02/31] perf tools: Don't set cmdline_group_boundary if no evsel is collected References: <1440822125-52691-1-git-send-email-wangnan0@huawei.com> <1440822125-52691-3-git-send-email-wangnan0@huawei.com> <20150831192003.GA2443@redhat.com> <20150901103848.GE12968@krava.brq.redhat.com> In-Reply-To: <20150901103848.GE12968@krava.brq.redhat.com> Content-Type: text/plain; charset="utf-8"; format=flowed Content-Transfer-Encoding: 7bit X-Originating-IP: [10.111.66.109] X-CFilter-Loop: Reflected X-Mirapoint-Virus-RAPID-Raw: score=unknown(0), refid=str=0001.0A020205.55E59E33.0051,ss=1,re=0.000,recu=0.000,reip=0.000,cl=1,cld=1,fgs=0, ip=0.0.0.0, so=2013-05-26 15:14:31, dmn=2013-03-21 17:37:32 X-Mirapoint-Loop-Id: 7b33d467086871a86d03938cbd9d8a02 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2015/9/1 18:38, Jiri Olsa wrote: > On Mon, Aug 31, 2015 at 04:20:03PM -0300, Arnaldo Carvalho de Melo wrote: >> Em Sat, Aug 29, 2015 at 04:21:36AM +0000, Wang Nan escreveu: >>> If parse_events__scanner() collects no entry, perf_evlist__last(evlist) >>> is invalid. Then setting of cmdline_group_boundary touches invalid. >>> >>> It could happend in currect BPF implementation. See [1]. Although it >>> can be fixed, for safety reason it whould be better to introduce this >>> check. >>> >>> Instead of checking number of entries, check data.list instead, so we >>> can add dummy evsel here. >> Event parsing fixes should have Jiri Olsa on the CC list, Jiri, is this >> ok? >> >> From what I can see it looks Ok, my question, just from looking at this >> patch, is if it is valid to get to this point with an empty data.list, >> i.e. was it ever possible and this is a bug irrespective of eBPF? > good point, I believe it's either fail or event(s) added to the list > I haven't checked how's eBPF connected with event parsing, is there a > git tree I could check? Please check: https://git.kernel.org/cgit/linux/kernel/git/pi3orama/linux.git/log/?h=perf/ebpf commit d7d91228cad0a78eae5ea9526a8a78debf3cf584 commit 2606fe61219899cb386823eddc1bc231ff5067a6 related to parsing. Thank you. > thanks, > jirka