From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751903AbZHJHXO (ORCPT ); Mon, 10 Aug 2009 03:23:14 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751242AbZHJHXN (ORCPT ); Mon, 10 Aug 2009 03:23:13 -0400 Received: from bombadil.infradead.org ([18.85.46.34]:58287 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751211AbZHJHXN (ORCPT ); Mon, 10 Aug 2009 03:23:13 -0400 Subject: Re: [PATCH 3/3] perfcounter: Align ftrace events raw samples to 8 bytes From: Peter Zijlstra To: Frederic Weisbecker Cc: Ingo Molnar , LKML , Arnaldo Carvalho de Melo , Mike Galbraith , Paul Mackerras In-Reply-To: <1249698400-5441-6-git-send-email-fweisbec@gmail.com> References: <1249698400-5441-1-git-send-email-fweisbec@gmail.com> <1249698400-5441-6-git-send-email-fweisbec@gmail.com> Content-Type: text/plain Content-Transfer-Encoding: 7bit Date: Mon, 10 Aug 2009 09:13:57 +0200 Message-Id: <1249888437.17467.42.camel@twins> Mime-Version: 1.0 X-Mailer: Evolution 2.26.1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, 2009-08-08 at 04:26 +0200, Frederic Weisbecker wrote: > Align the ftrace events raw samples to 8 bytes so that they meet the > perf output event alignements requirements. > > Reported-by: Peter Zijlstra > Signed-off-by: Frederic Weisbecker > Cc: Peter Zijlstra > Cc: Arnaldo Carvalho de Melo > Cc: Mike Galbraith > Cc: Paul Mackerras > --- > include/trace/ftrace.h | 2 +- > 1 files changed, 1 insertions(+), 1 deletions(-) > > diff --git a/include/trace/ftrace.h b/include/trace/ftrace.h > index 80e5f6c..7b0834c 100644 > --- a/include/trace/ftrace.h > +++ b/include/trace/ftrace.h > @@ -687,7 +687,7 @@ static void ftrace_profile_##call(proto) \ > pc = preempt_count(); \ > \ > __data_size = ftrace_get_offsets_##call(&__data_offsets, args); \ > - __entry_size = __data_size + sizeof(*entry); \ > + __entry_size = ALIGN(__data_size + sizeof(*entry), sizeof(u64));\ > \ > do { \ > char raw_data[__entry_size]; \ Make sure to clear the trailing few bytes, otherwise we've got a stack data leak here. Also, tracepoints using __string() could still easily overflow the stack here and cause great havoc, esp since the tracepoint could already be deep into a call-chain.