From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753181AbaHMQDA (ORCPT ); Wed, 13 Aug 2014 12:03:00 -0400 Received: from mail9.hitachi.co.jp ([133.145.228.44]:54948 "EHLO mail9.hitachi.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750757AbaHMQC7 (ORCPT ); Wed, 13 Aug 2014 12:02:59 -0400 Message-ID: <53EB8C2C.9030709@hitachi.com> Date: Thu, 14 Aug 2014 01:02:52 +0900 From: Masami Hiramatsu Organization: Hitachi, Ltd., Japan User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:13.0) Gecko/20120614 Thunderbird/13.0.1 MIME-Version: 1.0 To: Arnaldo Carvalho de Melo Cc: Namhyung Kim , Naohiro Aota , Ingo Molnar , Paul Mackerras , Peter Zijlstra , LKML Subject: Re: [PATCH 1/2] [BUGFIX] perf probe: Fix --list option to show events only with uprobe events References: <20140813005055.24360.73553.stgit@kbuild-fedora.novalocal> <87r40ldkv8.fsf@sejong.aot.lge.com> <53EB746E.1020904@hitachi.com> <20140813144801.GA2718@kernel.org> In-Reply-To: <20140813144801.GA2718@kernel.org> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org (2014/08/13 23:48), Arnaldo Carvalho de Melo wrote: > Em Wed, Aug 13, 2014 at 11:21:34PM +0900, Masami Hiramatsu escreveu: >> (2014/08/13 14:22), Namhyung Kim wrote: >>> On Wed, 13 Aug 2014 00:50:55 +0000, Masami Hiramatsu wrote: >>>> + if (kp_fd < 0 && up_fd < 0) { >>>> + /* Both kprobes and uprobes are disabled, warn it. */ >>>> + if (kp_fd == -ENOTSUP && up_fd == -ENOTSUP) >>>> + pr_warning("Debugfs is not mounted.\n"); >>>> + else if (kp_fd == -ENOENT && up_fd == -ENOENT) >>>> + pr_warning("Please rebuild kernel with " >>>> + "CONFIG_KPROBE_EVENTS or/and " >>>> + "CONFIG_UPROBE_EVENTS.\n"); >>>> + else >>>> + pr_warning("Failed to open kprobe events: %s.\n" \ >>>> + "Failed to open uprobe events: %s.\n", >>>> + strerror(-kp_fd), strerror(-up_fd)); >>> >>> It seems the second strerror() might overwrite the message of the >>> first. You'd better using strerror_r() IMHO. > > Well spotted! > >> Oops, right, it must use the same buffer... >> But instead of using strerror_r, we can call pr_warning twice. Or should we >> better replace all strerror to strerror_r in perf? (it should be another series) > > Well, don't introduce new strerror() uses, we have threads in perf > already and if both try to use strerror() for different reasons, say the > UI to print something to the user and some logging/debugging thread do > it to the disk, we may race. OK, I'll use strerror_r() in next version. > So, in this case, please use strerror_r() and if you feel like > contributing the changes to any other place where strerror() is still > used, you are welcome to do so at a later patch :) Yeah, I'll do that. :) Thank you! -- Masami HIRAMATSU Software Platform Research Dept. Linux Technology Research Center Hitachi, Ltd., Yokohama Research Laboratory E-mail: masami.hiramatsu.pt@hitachi.com