From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755276AbbIAKiw (ORCPT ); Tue, 1 Sep 2015 06:38:52 -0400 Received: from mx1.redhat.com ([209.132.183.28]:38343 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753095AbbIAKiv (ORCPT ); Tue, 1 Sep 2015 06:38:51 -0400 Date: Tue, 1 Sep 2015 12:38:48 +0200 From: Jiri Olsa To: Arnaldo Carvalho de Melo Cc: Jiri Olsa , Wang Nan , mingo@kernel.org, ast@plumgrid.com, linux-kernel@vger.kernel.org, lizefan@huawei.com, pi3orama@163.com, Masami Hiramatsu , Namhyung Kim Subject: Re: [PATCH 02/31] perf tools: Don't set cmdline_group_boundary if no evsel is collected Message-ID: <20150901103848.GE12968@krava.brq.redhat.com> References: <1440822125-52691-1-git-send-email-wangnan0@huawei.com> <1440822125-52691-3-git-send-email-wangnan0@huawei.com> <20150831192003.GA2443@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20150831192003.GA2443@redhat.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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? thanks, jirka