From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756144AbZCXN4w (ORCPT ); Tue, 24 Mar 2009 09:56:52 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754628AbZCXN4O (ORCPT ); Tue, 24 Mar 2009 09:56:14 -0400 Received: from hrndva-omtalb.mail.rr.com ([71.74.56.123]:54296 "EHLO hrndva-omtalb.mail.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754341AbZCXN4M (ORCPT ); Tue, 24 Mar 2009 09:56:12 -0400 Message-Id: <20090324135610.248663698@goodmis.org> References: <20090324135422.026619569@goodmis.org> User-Agent: quilt/0.46-1 Date: Tue, 24 Mar 2009 09:54:24 -0400 From: Steven Rostedt To: linux-kernel@vger.kernel.org Cc: Ingo Molnar , Andrew Morton , Peter Zijlstra , Thomas Gleixner , Frederic Weisbecker , Steven Rostedt Subject: [PATCH 2/3] function-graph: prevent more than one tracer registering Content-Disposition: inline; filename=0002-function-graph-prevent-more-than-one-tracer-registe.patch Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Steven Rostedt Impact: prevent crash due to multiple function graph tracers The function graph tracer can currently only handle a single tracer being registered. If another tracer registers with the function graph tracer it can crash the system. Signed-off-by: Steven Rostedt --- kernel/trace/ftrace.c | 6 ++++++ 1 files changed, 6 insertions(+), 0 deletions(-) diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 7847806..c81a759 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -2643,6 +2643,12 @@ int register_ftrace_graph(trace_func_graph_ret_t retfunc, mutex_lock(&ftrace_lock); + /* we currently allow only one tracer registered at a time */ + if (atomic_read(&ftrace_graph_active)) { + ret = -EBUSY; + goto out; + } + ftrace_suspend_notifier.notifier_call = ftrace_suspend_notifier_call; register_pm_notifier(&ftrace_suspend_notifier); -- 1.6.2 --