Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932933AbcJNN0M (ORCPT ); Fri, 14 Oct 2016 09:26:12 -0400 Received: from mail-yb0-f173.google.com ([209.85.213.173]:33853 "EHLO mail-yb0-f173.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932193AbcJNNZl (ORCPT ); Fri, 14 Oct 2016 09:25:41 -0400 MIME-Version: 1.0 In-Reply-To: <20161014111359.GB12815@kernel.org> References: <1476356383-30100-1-git-send-email-eranian@google.com> <1476356383-30100-2-git-send-email-eranian@google.com> <20161014111359.GB12815@kernel.org> From: Stephane Eranian Date: Fri, 14 Oct 2016 05:57:25 -0700 Message-ID: Subject: Re: [PATCH 1/9] perf/jit: improve error messages from JVMTI To: Arnaldo Carvalho de Melo Cc: Nilay Vaish , Linux Kernel list , Jiri Olsa , Peter Zijlstra , "mingo@elte.hu" , Anton Blanchard , Namhyung Kim Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1783 Lines: 43 On Fri, Oct 14, 2016 at 4:13 AM, Arnaldo Carvalho de Melo wrote: > Em Thu, Oct 13, 2016 at 03:05:40PM -0500, Nilay Vaish escreveu: >> On 13 October 2016 at 05:59, Stephane Eranian wrote: >> > +++ b/tools/perf/jvmti/libjvmti.c >> > @@ -12,6 +12,17 @@ >> > +static void print_error(jvmtiEnv *jvmti, const char *msg, jvmtiError ret) >> > +{ >> > + char *err_msg = NULL; >> > + jvmtiError err; >> > + err = (*jvmti)->GetErrorName(jvmti, ret, &err_msg); >> > + if (err == JVMTI_ERROR_NONE) { >> > + warnx("%s failed with %s", msg, err_msg); >> > + (*jvmti)->Deallocate(jvmti, (unsigned char *)err_msg); >> > + } >> > +} >> >> Do we not need to release the memory for err_msg if the condition for >> the 'if' statement evaluates to false? Is it that we are going to >> kill the process, so no need to release the memory? > > I guess that print_error() is called only when an error was returned > somewhere, that ret parameter, then if there was no error > (JVMTI_ERROR_NONE) in translating that numeric code to an string, > err_msg, it can then be used with warnx() (the main purpose of > print_error()) and then deallocated. > > For err != JVMTI_ERROR_NONE it silently goes back to the caller that > expected it to print something. > > I.e. probably it should have an else clause, something like: > > if (err == JVMTI_ERROR_NONE) { > warnx("%s failed with %s", msg, err_msg); > (*jvmti)->Deallocate(jvmti, (unsigned char *)err_msg); > } else { > warnx("%s failed with an unknown error %d", msg, (int)ret); > } > > Stephane? >'I will fix all of the comments over the week-end. I am away from office today. > - Arnaldo