From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755419AbYKNXAa (ORCPT ); Fri, 14 Nov 2008 18:00:30 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751696AbYKNXAS (ORCPT ); Fri, 14 Nov 2008 18:00:18 -0500 Received: from smtp.polymtl.ca ([132.207.4.11]:52172 "EHLO smtp.polymtl.ca" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751579AbYKNXAR (ORCPT ); Fri, 14 Nov 2008 18:00:17 -0500 Message-Id: <20081114224948.632083242@polymtl.ca> References: <20081114224733.364965865@polymtl.ca> User-Agent: quilt/0.46-1 Date: Fri, 14 Nov 2008 17:47:42 -0500 From: Mathieu Desnoyers To: Ingo Molnar , linux-kernel@vger.kernel.org Cc: akpm@linux-foundation.org, Linus Torvalds , Mathieu Desnoyers , Lai Jiangshan Subject: [patch 09/16] Tracepoint fix disable Content-Disposition: inline; filename=tracepoint-fix-disable.patch X-Poly-FromMTA: (test.casi.polymtl.ca [132.207.72.60]) at Fri, 14 Nov 2008 23:00:02 +0000 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Set the probe array pointer to NULL when the tracepoint is disabled. The probe array point not being NULL could generate a race condition where the reader would dereference a freed pointer. Impact: bugfix. Signed-off-by: Mathieu Desnoyers CC: 'Ingo Molnar' CC: Lai Jiangshan --- kernel/tracepoint.c | 1 + 1 file changed, 1 insertion(+) Index: linux.trees.git/kernel/tracepoint.c =================================================================== --- linux.trees.git.orig/kernel/tracepoint.c 2008-11-14 17:39:52.000000000 -0500 +++ linux.trees.git/kernel/tracepoint.c 2008-11-14 17:39:56.000000000 -0500 @@ -262,6 +262,7 @@ static void set_tracepoint(struct tracep static void disable_tracepoint(struct tracepoint *elem) { elem->state = 0; + rcu_assign_pointer(elem->funcs, NULL); } /** -- Mathieu Desnoyers OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68