Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934646AbaFSVEA (ORCPT ); Thu, 19 Jun 2014 17:04:00 -0400 Received: from e39.co.us.ibm.com ([32.97.110.160]:55439 "EHLO e39.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934613AbaFSVD6 (ORCPT ); Thu, 19 Jun 2014 17:03:58 -0400 Date: Thu, 19 Jun 2014 13:53:36 -0700 From: "Paul E. McKenney" To: Sasha Levin Cc: Thomas Gleixner , Christoph Lameter , Pekka Enberg , Matt Mackall , Andrew Morton , Dave Jones , "linux-mm@kvack.org" , LKML Subject: Re: slub/debugobjects: lockup when freeing memory Message-ID: <20140619205336.GM4904@linux.vnet.ibm.com> Reply-To: paulmck@linux.vnet.ibm.com References: <53A2F406.4010109@oracle.com> <20140619165247.GA4904@linux.vnet.ibm.com> <20140619202928.GG4904@linux.vnet.ibm.com> <53A34B23.1000401@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <53A34B23.1000401@oracle.com> User-Agent: Mutt/1.5.21 (2010-09-15) X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 14061920-9332-0000-0000-000001256D3C Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jun 19, 2014 at 04:42:11PM -0400, Sasha Levin wrote: > On 06/19/2014 04:29 PM, Paul E. McKenney wrote: > > rcu: Provide call_rcu_alloc() and call_rcu_sched_alloc() to avoid recursion > > > > The sl*b allocators use call_rcu() to manage object lifetimes, but > > call_rcu() can use debug-objects, which in turn invokes the sl*b > > allocators. These allocators are not prepared for this sort of > > recursion, which can result in failures. > > > > This commit therefore creates call_rcu_alloc() and call_rcu_sched_alloc(), > > which act as their call_rcu() and call_rcu_sched() counterparts, but > > which avoid invoking debug-objects. These new API members are intended > > only for use by the sl*b allocators, and this commit makes the sl*b > > allocators use call_rcu_alloc(). Why call_rcu_sched_alloc()? Because > > in CONFIG_PREEMPT=n kernels, call_rcu() maps to call_rcu_sched(), so > > therefore call_rcu_alloc() must map to call_rcu_sched_alloc(). > > > > Reported-by: Sasha Levin > > Set-straight-by: Thomas Gleixner > > Signed-off-by: Paul E. McKenney > > Paul, what is this patch based on? It won't apply cleanly on -next > or Linus's tree. On my -rcu tree, but I think that Thomas's approach is better. Thanx, 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/