From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755386Ab0C3De2 (ORCPT ); Mon, 29 Mar 2010 23:34:28 -0400 Received: from mail.openrapids.net ([64.15.138.104]:52099 "EHLO blackscsi.openrapids.net" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751666Ab0C3De1 (ORCPT ); Mon, 29 Mar 2010 23:34:27 -0400 Date: Mon, 29 Mar 2010 23:34:25 -0400 From: Mathieu Desnoyers To: linux-kernel@vger.kernel.org Cc: Randy Dunlap , Eric Dumazet , Rusty Russell , Peter Zijlstra , Tejun Heo , Ingo Molnar , Andrew Morton , Linus Torvalds , Greg Kroah-Hartman , Steven Rostedt , stable Subject: [PATCH] lockdep fix incorrect percpu usage Message-ID: <20100330033425.GD7683@Krystal> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline X-Editor: vi X-Info: http://www.efficios.com X-Operating-System: Linux/2.6.26-2-686 (i686) X-Uptime: 23:32:12 up 66 days, 6:09, 4 users, load average: 0.18, 0.10, 0.03 User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Should use per_cpu_ptr() to obfuscate the per cpu pointers (RELOC_HIDE is needed for per cpu pointers). git blame points to commit: lockdep.c: commit 8e18257d29238311e82085152741f0c3aa18b74d But it's really just moving the code around. But it's enough to say that the problems appeared before Jul 19 01:48:54 2007, which brings us back to 2.6.23. So it should be applied to stable 2.6.23.x to 2.6.33.x (or whichever of these stable branches are still maintained) and to mainline 2.6.34-rc2. This patch should be queued for the stable branch. (tested on 2.6.33.1 x86_64) Signed-off-by: Mathieu Desnoyers CC: Randy Dunlap CC: Eric Dumazet CC: Rusty Russell CC: Peter Zijlstra CC: Tejun Heo CC: Ingo Molnar CC: Andrew Morton CC: Linus Torvalds CC: Greg Kroah-Hartman CC: Steven Rostedt CC: stable --- kernel/lockdep.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) Index: linux-2.6-lttng/kernel/lockdep.c =================================================================== --- linux-2.6-lttng.orig/kernel/lockdep.c 2010-03-29 23:54:31.000000000 -0400 +++ linux-2.6-lttng/kernel/lockdep.c 2010-03-29 23:54:38.000000000 -0400 @@ -609,9 +609,9 @@ static int static_obj(void *obj) * percpu var? */ for_each_possible_cpu(i) { - start = (unsigned long) &__per_cpu_start + per_cpu_offset(i); - end = (unsigned long) &__per_cpu_start + PERCPU_ENOUGH_ROOM - + per_cpu_offset(i); + start = (unsigned long) per_cpu_ptr(&__per_cpu_start, i); + end = (unsigned long) per_cpu_ptr(&__per_cpu_start + + PERCPU_ENOUGH_ROOM, i); if ((addr >= start) && (addr < end)) return 1; -- Mathieu Desnoyers Operating System Efficiency R&D Consultant EfficiOS Inc. http://www.efficios.com