Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934464AbaFSU22 (ORCPT ); Thu, 19 Jun 2014 16:28:28 -0400 Received: from www.linutronix.de ([62.245.132.108]:55336 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754264AbaFSU21 (ORCPT ); Thu, 19 Jun 2014 16:28:27 -0400 Date: Thu, 19 Jun 2014 22:28:14 +0200 (CEST) From: Thomas Gleixner To: Christoph Lameter cc: "Paul E. McKenney" , Sasha Levin , Pekka Enberg , Matt Mackall , Andrew Morton , Dave Jones , "linux-mm@kvack.org" , LKML Subject: Re: slub/debugobjects: lockup when freeing memory In-Reply-To: Message-ID: References: <53A2F406.4010109@oracle.com> <20140619165247.GA4904@linux.vnet.ibm.com> User-Agent: Alpine 2.10 (DEB 1266 2009-07-14) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1,SHORTCIRCUIT=-0.0001 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 19 Jun 2014, Christoph Lameter wrote: > On Thu, 19 Jun 2014, Thomas Gleixner wrote: > > > Well, no. Look at the callchain: > > > > __call_rcu > > debug_object_activate > > rcuhead_fixup_activate > > debug_object_init > > kmem_cache_alloc > > > > So call rcu activates the object, but the object has no reference in > > the debug objects code so the fixup code is called which inits the > > object and allocates a reference .... > > So we need to init the object in the page struct before the __call_rcu? Looks like RCU is lazily relying on the state callback to initialize the objects. There is an unused debug_init_rcu_head() inline in kernel/rcu/update.c Paul???? -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/