From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail137.messagelabs.com (mail137.messagelabs.com [216.82.249.19]) by kanga.kvack.org (Postfix) with ESMTP id E76E69000DF for ; Mon, 3 Oct 2011 17:07:09 -0400 (EDT) Subject: Re: lockdep recursive locking detected (rcu_kthread / __cache_free) From: Peter Zijlstra Date: Mon, 03 Oct 2011 23:06:19 +0200 In-Reply-To: References: <20111003175322.GA26122@sucs.org> <20111003203139.GH2403@linux.vnet.ibm.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Message-ID: <1317675980.9417.1.camel@twins> Mime-Version: 1.0 Sender: owner-linux-mm@kvack.org List-ID: To: Christoph Lameter Cc: "Paul E. McKenney" , Sitsofe Wheeler , Ingo Molnar , linux-kernel@vger.kernel.org, penberg@kernel.org, mpm@selenic.com, linux-mm@kvack.org On Mon, 2011-10-03 at 15:46 -0500, Christoph Lameter wrote: > On Mon, 3 Oct 2011, Paul E. McKenney wrote: >=20 > > The first lock was acquired here in an RCU callback. The later lock th= at > > lockdep complained about appears to have been acquired from a recursive > > call to __cache_free(), with no help from RCU. This looks to me like > > one of the issues that arise from the slab allocator using itself to > > allocate slab metadata. >=20 > Right. However, this is a false positive since the slab cache with > the metadata is different from the slab caches with the slab data. The sl= ab > cache with the metadata does not use itself any metadata slab caches. Sure, but we're supposed to have annotated that.. see init_node_lock_keys() -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org