From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755978Ab1G0V4l (ORCPT ); Wed, 27 Jul 2011 17:56:41 -0400 Received: from mga02.intel.com ([134.134.136.20]:16729 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755706Ab1G0VtQ (ORCPT ); Wed, 27 Jul 2011 17:49:16 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.67,279,1309762800"; d="scan'208";a="32826540" From: Andi Kleen References: <20110727247.325703029@firstfloor.org> In-Reply-To: <20110727247.325703029@firstfloor.org> To: marcin.slusarz@gmail.com, catalin.marinas@arm.com, tj@kernel.org, dipankar@in.ibm.com, paulmck@linux.vnet.ibm.com, ak@linux.intel.com, tglx@linutronix.de, gregkh@suse.de, linux-kernel@vger.kernel.org, stable@kernel.org, tim.bird@am.sony.com Subject: [PATCH] [76/99] debugobjects: Fix boot crash when kmemleak and debugobjects enabled Message-Id: <20110727214915.A769F2403FF@tassilo.jf.intel.com> Date: Wed, 27 Jul 2011 14:49:15 -0700 (PDT) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 2.6.35-longterm review patch. If anyone has any objections, please let me know. ------------------ From: Marcin Slusarz commit 161b6ae0e067e421b20bb35caf66bdb405c929ac upstream. Order of initialization look like this: ... debugobjects kmemleak ...(lots of other subsystems)... workqueues (through early initcall) ... debugobjects use schedule_work for batch freeing of its data and kmemleak heavily use debugobjects, so when it comes to freeing and workqueues were not initialized yet, kernel crashes: BUG: unable to handle kernel NULL pointer dereference at (null) IP: [] __queue_work+0x29/0x41a [] queue_work_on+0x16/0x1d [] queue_work+0x29/0x55 [] schedule_work+0x13/0x15 [] free_object+0x90/0x95 [] debug_check_no_obj_freed+0x187/0x1d3 [] ? _raw_spin_unlock_irqrestore+0x30/0x4d [] ? free_object_rcu+0x68/0x6d [] kmem_cache_free+0x64/0x12c [] free_object_rcu+0x68/0x6d [] __rcu_process_callbacks+0x1b6/0x2d9 ... because system_wq is NULL. Fix it by checking if workqueues susbystem was initialized before using. Signed-off-by: Marcin Slusarz Cc: Catalin Marinas Cc: Tejun Heo Cc: Dipankar Sarma Cc: Paul E. McKenney Signed-off-by: Andi Kleen Link: http://lkml.kernel.org/r/20110528112342.GA3068@joi.lan Signed-off-by: Thomas Gleixner Signed-off-by: Greg Kroah-Hartman --- lib/debugobjects.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) Index: linux-2.6.35.y/lib/debugobjects.c =================================================================== --- linux-2.6.35.y.orig/lib/debugobjects.c +++ linux-2.6.35.y/lib/debugobjects.c @@ -198,7 +198,7 @@ static void free_object(struct debug_obj * initialized: */ if (obj_pool_free > ODEBUG_POOL_SIZE && obj_cache) - sched = !work_pending(&debug_obj_work); + sched = keventd_up() && !work_pending(&debug_obj_work); hlist_add_head(&obj->node, &obj_pool); obj_pool_free++; obj_pool_used--;