From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753966AbaBKTHe (ORCPT ); Tue, 11 Feb 2014 14:07:34 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:40274 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753804AbaBKTHb (ORCPT ); Tue, 11 Feb 2014 14:07:31 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Steven Rostedt Subject: [PATCH 3.10 03/79] tracing: Check if tracing is enabled in trace_puts() Date: Tue, 11 Feb 2014 11:05:07 -0800 Message-Id: <20140211184721.034388642@linuxfoundation.org> X-Mailer: git-send-email 1.8.5.1.163.gd7aced9 In-Reply-To: <20140211184720.928667275@linuxfoundation.org> References: <20140211184720.928667275@linuxfoundation.org> User-Agent: quilt/0.61-1 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.10-stable review patch. If anyone has any objections, please let me know. ------------------ From: "Steven Rostedt (Red Hat)" commit 3132e107d608f8753240d82d61303c500fd515b4 upstream. 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. Fixes: 09ae72348ecc "tracing: Add trace_puts() for even faster trace_printk() tracing" Signed-off-by: Steven Rostedt Signed-off-by: Greg Kroah-Hartman --- kernel/trace/trace.c | 6 ++++++ 1 file changed, 6 insertions(+) --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -424,6 +424,9 @@ int __trace_puts(unsigned long ip, const 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); @@ -464,6 +467,9 @@ int __trace_bputs(unsigned long ip, cons 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,