From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754086Ab0F3IvU (ORCPT ); Wed, 30 Jun 2010 04:51:20 -0400 Received: from e28smtp07.in.ibm.com ([122.248.162.7]:60893 "EHLO e28smtp07.in.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751799Ab0F3IvS (ORCPT ); Wed, 30 Jun 2010 04:51:18 -0400 Date: Wed, 30 Jun 2010 14:15:48 +0530 From: Srikar Dronamraju To: Ingo Molnar , Masami Hiramatsu Cc: Linus Torvalds , Srikar Dronamraju , LKML Subject: [Bugfix] unregister_trace_probe needs to be called under mutex Message-ID: <20100630084548.GA10325@linux.vnet.ibm.com> Reply-To: Srikar Dronamraju MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 --- 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; }