Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757822AbZCMJ0X (ORCPT ); Fri, 13 Mar 2009 05:26:23 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753859AbZCMJ0N (ORCPT ); Fri, 13 Mar 2009 05:26:13 -0400 Received: from mx3.mail.elte.hu ([157.181.1.138]:50809 "EHLO mx3.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751517AbZCMJ0N (ORCPT ); Fri, 13 Mar 2009 05:26:13 -0400 Date: Fri, 13 Mar 2009 10:25:58 +0100 From: Ingo Molnar To: Zhaolei Cc: "Steven Rostedt ;" , linux-kernel@vger.kernel.org Subject: Re: [PATCH] ftrace: Avoid double-free of dyn_ftrace Message-ID: <20090313092558.GD2571@elte.hu> References: <49BA23D9.1050900@cn.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <49BA23D9.1050900@cn.fujitsu.com> User-Agent: Mutt/1.5.18 (2008-05-17) X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -1.5 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-1.5 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.2.3 -1.5 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1173 Lines: 36 * Zhaolei wrote: > If dyn_ftrace is free before ftrace_release(), > ftrace_release() will free it again and make > ftrace_free_records wrong. > > Signed-off-by: Zhao Lei > --- > kernel/trace/ftrace.c | 3 ++- > 1 files changed, 2 insertions(+), 1 deletions(-) > > diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c > index d33d306..26c45aa 100644 > --- a/kernel/trace/ftrace.c > +++ b/kernel/trace/ftrace.c > @@ -356,7 +356,8 @@ void ftrace_release(void *start, unsigned long size) > > mutex_lock(&ftrace_lock); > do_for_each_ftrace_rec(pg, rec) { > - if ((rec->ip >= s) && (rec->ip < e)) > + if ((rec->ip >= s) && (rec->ip < e) && > + !(rec->flags & FTRACE_FL_FREE)) > ftrace_free_rec(rec); Applied to tip:tracing/ftrace, thanks! I'm wondering, did you trigger this in practice (if yes, how?), or have you found it via code review? Ingo -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/