From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759259Ab2JKULR (ORCPT ); Thu, 11 Oct 2012 16:11:17 -0400 Received: from hrndva-omtalb.mail.rr.com ([71.74.56.122]:28141 "EHLO hrndva-omtalb.mail.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757224Ab2JKULN (ORCPT ); Thu, 11 Oct 2012 16:11:13 -0400 X-Authority-Analysis: v=2.0 cv=a96yBDuF c=1 sm=0 a=rXTBtCOcEpjy1lPqhTCpEQ==:17 a=mNMOxpOpBa8A:10 a=SDt48C6ByX4A:10 a=5SG0PmZfjMsA:10 a=Q9fys5e9bTEA:10 a=meVymXHHAAAA:8 a=l7_9tSXZjzcA:10 a=VwQbUJbxAAAA:8 a=1XWaLZrsAAAA:8 a=AS1RrZ5PnTC0n6Uu3PkA:9 a=PUjeQqilurYA:10 a=UTB_XpHje0EA:10 a=jeBq3FmKZ4MA:10 a=zB3R35yRSVL3cNGO:21 a=1vT9WK16aYhReYGp:21 a=rXTBtCOcEpjy1lPqhTCpEQ==:117 X-Cloudmark-Score: 0 X-Originating-IP: 74.67.115.198 Message-ID: <1349986271.24256.67.camel@gandalf.local.home> Subject: [PATCH][3.7] ring-buffer: Check for uninitialized cpu buffer before resizing From: Steven Rostedt To: LKML Cc: Ingo Molnar , stable , Vaibhav Nagarnaik Date: Thu, 11 Oct 2012 16:11:11 -0400 Content-Type: text/plain; charset="ISO-8859-15" X-Mailer: Evolution 3.4.3-1 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Ingo, Please pull the latest tip/perf/urgent tree, which can be found at: git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace.git tip/perf/urgent Head SHA1: 8e49f418c9632790bf456634742d34d97120a784 Vaibhav Nagarnaik (1): ring-buffer: Check for uninitialized cpu buffer before resizing ---- kernel/trace/ring_buffer.c | 4 ++++ 1 file changed, 4 insertions(+) --------------------------- commit 8e49f418c9632790bf456634742d34d97120a784 Author: Vaibhav Nagarnaik Date: Wed Oct 10 16:40:27 2012 -0700 ring-buffer: Check for uninitialized cpu buffer before resizing With a system where, num_present_cpus < num_possible_cpus, even if all CPUs are online, non-present CPUs don't have per_cpu buffers allocated. If per_cpu//buffer_size_kb is modified for such a CPU, it can cause a panic due to NULL dereference in ring_buffer_resize(). To fix this, resize operation is allowed only if the per-cpu buffer has been initialized. Link: http://lkml.kernel.org/r/1349912427-6486-1-git-send-email-vnagarnaik@google.com Cc: stable@vger.kernel.org # 3.5+ Signed-off-by: Vaibhav Nagarnaik Signed-off-by: Steven Rostedt diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index b32ed0e..b979426 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -1567,6 +1567,10 @@ int ring_buffer_resize(struct ring_buffer *buffer, unsigned long size, put_online_cpus(); } else { + /* Make sure this CPU has been intitialized */ + if (!cpumask_test_cpu(cpu_id, buffer->cpumask)) + goto out; + cpu_buffer = buffer->buffers[cpu_id]; if (nr_pages == cpu_buffer->nr_pages)