From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751656Ab0GABJO (ORCPT ); Wed, 30 Jun 2010 21:09:14 -0400 Received: from mail7.hitachi.co.jp ([133.145.228.42]:39864 "EHLO mail7.hitachi.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751535Ab0GABJM (ORCPT ); Wed, 30 Jun 2010 21:09:12 -0400 X-AuditID: b753bd60-a9e06ba000007d15-e0-4c2beab5e948 Message-ID: <4C2BEAAF.8050103@hitachi.com> Date: Thu, 01 Jul 2010 10:09:03 +0900 From: Masami Hiramatsu Organization: Systems Development Lab., Hitachi, Ltd., Japan User-Agent: Thunderbird 2.0.0.24 (Windows/20100228) MIME-Version: 1.0 To: Srikar Dronamraju Cc: Ingo Molnar , Linus Torvalds , LKML Subject: Re: [Bugfix] unregister_trace_probe needs to be called under mutex References: <20100630084548.GA10325@linux.vnet.ibm.com> In-Reply-To: <20100630084548.GA10325@linux.vnet.ibm.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-Brightmail-Tracker: AAAAAA== X-FMFTCR: RANGEC Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Srikar Dronamraju wrote: > Comment in unregister_trace_probe() says probe_lock will be held > when it gets called. However there is a case where it might called > without the probe_lock being held. Also since we are traversing the > probe_list and deleting an element from the probe_list, probe_lock > should be held. > > This was first pointed in uprobes traceevent review by Frederic > Weisbecker here. (http://lkml.org/lkml/2010/5/12/106) > > This patch is needed for both 2.6.35-rc3 and 2.6.35-rc3-tip > > Signed-off-by: Srikar Dronamraju Ah, right! That's definately needed. Acked-by: Masami Hiramatsu Thank you! > --- > > diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c > index 4f11a56..67670cd 100644 > --- a/kernel/trace/trace_kprobe.c > +++ b/kernel/trace/trace_kprobe.c > @@ -269,14 +269,17 @@ static int create_trace_probe(int argc, char **argv) > pr_info("Delete command needs an event name.\n"); > return -EINVAL; > } > + mutex_lock(&probe_lock); > tp = find_probe_event(event, group); > if (!tp) { > + mutex_unlock(&probe_lock); > pr_info("Event %s/%s doesn't exist.\n", group, event); > return -ENOENT; > } > /* delete an event */ > unregister_trace_probe(tp); > free_trace_probe(tp); > + mutex_unlock(&probe_lock); > return 0; > } >