From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757660AbZHHCap (ORCPT ); Fri, 7 Aug 2009 22:30:45 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754637AbZHHCao (ORCPT ); Fri, 7 Aug 2009 22:30:44 -0400 Received: from mail-bw0-f219.google.com ([209.85.218.219]:41457 "EHLO mail-bw0-f219.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754547AbZHHCan (ORCPT ); Fri, 7 Aug 2009 22:30:43 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=date:from:to:cc:subject:message-id:references:mime-version :content-type:content-disposition:content-transfer-encoding :in-reply-to:user-agent; b=OlMIxPRmne2eG9dGnLSEWW73Fej46Xj0lm8aizGd0tC1yclt/W96SVcJ90f6z3JtHa U8o/ECgA4HAOZA5rUUb2TYJNzc0JyIArF2OUsYs6AVm+1dsMyh5HP//a6oo43iy5r/Z0 8itPLq8wC4lDifq65/7odd8/y/UsR4MsZd2Xk= Date: Sat, 8 Aug 2009 04:30:39 +0200 From: Frederic Weisbecker To: Ingo Molnar Cc: LKML , Peter Zijlstra , Arnaldo Carvalho de Melo , Mike Galbraith , Paul Mackerras Subject: Re: [PATCH 1/3] perfcounter: Initialize tracepoint record before any use Message-ID: <20090808023038.GA5366@nowhere> References: <1249698400-5441-1-git-send-email-fweisbec@gmail.com> <1249698400-5441-2-git-send-email-fweisbec@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <1249698400-5441-2-git-send-email-fweisbec@gmail.com> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Aug 08, 2009 at 04:26:35AM +0200, Frederic Weisbecker wrote: > Despite that the tracepoint record is always present when the > PERF_SAMPLE_TP_RECORD flag is set, gcc whines, thinking it might not > be initialized: > > kernel/perf_counter.c: In function ‘perf_counter_output’: > kernel/perf_counter.c:2650: warning: ‘tp’ may be used uninitialized in this function > > Then, initialize it to NULL and always check if it's not NULL before > dereference it. > > Reported-by: Ingo Molnar > Signed-off-by: Frederic Weisbecker > Cc: Peter Zijlstra > Cc: Arnaldo Carvalho de Melo > Cc: Mike Galbraith > Cc: Paul Mackerras > --- Hmm, sorry I've resent the perf tools series by mistake. Please ignore the [PATCH */4] "perf tools: *" series that has already been sent. The only ones are [PATCH */3] perfcounter: * Thanks. > kernel/perf_counter.c | 7 ++++--- > 1 files changed, 4 insertions(+), 3 deletions(-) > > diff --git a/kernel/perf_counter.c b/kernel/perf_counter.c > index 142ae5a..a6963e2 100644 > --- a/kernel/perf_counter.c > +++ b/kernel/perf_counter.c > @@ -2647,7 +2647,7 @@ void perf_counter_output(struct perf_counter *counter, int nmi, > u64 counter; > } group_entry; > struct perf_callchain_entry *callchain = NULL; > - struct perf_tracepoint_record *tp; > + struct perf_tracepoint_record *tp = NULL; > int callchain_size = 0; > u64 time; > struct { > @@ -2718,7 +2718,8 @@ void perf_counter_output(struct perf_counter *counter, int nmi, > > if (sample_type & PERF_SAMPLE_TP_RECORD) { > tp = data->private; > - header.size += tp->size; > + if (tp) > + header.size += tp->size; > } > > ret = perf_output_begin(&handle, counter, header.size, nmi, 1); > @@ -2784,7 +2785,7 @@ void perf_counter_output(struct perf_counter *counter, int nmi, > } > } > > - if (sample_type & PERF_SAMPLE_TP_RECORD) > + if ((sample_type & PERF_SAMPLE_TP_RECORD) && tp) > perf_output_copy(&handle, tp->record, tp->size); > > perf_output_end(&handle); > -- > 1.6.2.3 >