From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754823Ab2FZXZd (ORCPT ); Tue, 26 Jun 2012 19:25:33 -0400 Received: from mail-pz0-f46.google.com ([209.85.210.46]:51431 "EHLO mail-pz0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754357Ab2FZXZb (ORCPT ); Tue, 26 Jun 2012 19:25:31 -0400 From: Anton Vorontsov To: Greg Kroah-Hartman , Kees Cook , Colin Cross , Tony Luck , Steven Rostedt , Frederic Weisbecker , Ingo Molnar Cc: Arnd Bergmann , John Stultz , Shuah Khan , arve@android.com, Rebecca Schultz Zavin , Jesper Juhl , Randy Dunlap , Stephen Boyd , Thomas Meyer , Andrew Morton , Marco Stornelli , WANG Cong , linux-kernel@vger.kernel.org, devel@driverdev.osuosl.org, linaro-kernel@lists.linaro.org, patches@linaro.org, kernel-team@android.com Subject: [PATCH 1/7] tracing: Fix initialization failure path in tracing_set_tracer() Date: Tue, 26 Jun 2012 16:23:23 -0700 Message-Id: <1340753009-12483-1-git-send-email-anton.vorontsov@linaro.org> X-Mailer: git-send-email 1.7.10.4 In-Reply-To: <20120626232210.GA11549@lizard> References: <20120626232210.GA11549@lizard> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org If tracer->init() fails, current code will leave current_tracer pointing to an unusable tracer, which at best makes 'current_tracer' report inaccurate value. Fix the issue by pointing current_tracer to nop tracer, and only update current_tracer with the new one after all the initialization succeeds. Signed-off-by: Anton Vorontsov Acked-by: Steven Rostedt --- kernel/trace/trace.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index a7fa070..7647d33 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -3172,10 +3172,10 @@ static int tracing_set_tracer(const char *buf) } destroy_trace_option_files(topts); - current_trace = t; + current_trace = &nop_trace; - topts = create_trace_option_files(current_trace); - if (current_trace->use_max_tr) { + topts = create_trace_option_files(t); + if (t->use_max_tr) { int cpu; /* we need to make per cpu buffer sizes equivalent */ for_each_tracing_cpu(cpu) { @@ -3195,6 +3195,7 @@ static int tracing_set_tracer(const char *buf) goto out; } + current_trace = t; trace_branch_enable(tr); out: mutex_unlock(&trace_types_lock); -- 1.7.10.4