From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752785AbaAZFBZ (ORCPT ); Sun, 26 Jan 2014 00:01:25 -0500 Received: from cdptpa-outbound-snat.email.rr.com ([107.14.166.226]:29821 "EHLO cdptpa-oedge-vip.email.rr.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752515AbaAZFAm (ORCPT ); Sun, 26 Jan 2014 00:00:42 -0500 Message-Id: <20140126050030.429010716@goodmis.org> User-Agent: quilt/0.60-1 Date: Sat, 25 Jan 2014 23:59:44 -0500 From: Steven Rostedt To: linux-kernel@vger.kernel.org Cc: Ingo Molnar , Frederic Weisbecker , Andrew Morton Subject: [for-next][PATCH 3/3] tracing: Check if tracing is enabled in trace_puts() References: <20140126045941.796589415@goodmis.org> Content-Disposition: inline; filename=0003-tracing-Check-if-tracing-is-enabled-in-trace_puts.patch X-RR-Connecting-IP: 107.14.168.118:25 X-Cloudmark-Score: 0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: "Steven Rostedt (Red Hat)" If trace_puts() is used very early in boot up, it can crash the machine if it is called before the ring buffer is allocated. If a trace_printk() is used with no arguments, then it will be converted into a trace_puts() and suffer the same fate. Cc: stable@vger.kernel.org # 3.10+ Fixes: 09ae72348ecc "tracing: Add trace_puts() for even faster trace_printk() tracing" Signed-off-by: Steven Rostedt --- kernel/trace/trace.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 7857ea9..815c878 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -455,6 +455,9 @@ int __trace_puts(unsigned long ip, const char *str, int size) unsigned long irq_flags; int alloc; + if (unlikely(tracing_selftest_running || tracing_disabled)) + return 0; + alloc = sizeof(*entry) + size + 2; /* possible \n added */ local_save_flags(irq_flags); @@ -495,6 +498,9 @@ int __trace_bputs(unsigned long ip, const char *str) unsigned long irq_flags; int size = sizeof(struct bputs_entry); + if (unlikely(tracing_selftest_running || tracing_disabled)) + return 0; + local_save_flags(irq_flags); buffer = global_trace.trace_buffer.buffer; event = trace_buffer_lock_reserve(buffer, TRACE_BPUTS, size, -- 1.8.4.3