From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qe0-f52.google.com (mail-qe0-f52.google.com [209.85.128.52]) by kanga.kvack.org (Postfix) with ESMTP id 950556B0039 for ; Mon, 2 Dec 2013 12:18:18 -0500 (EST) Received: by mail-qe0-f52.google.com with SMTP id ne12so13735130qeb.39 for ; Mon, 02 Dec 2013 09:18:18 -0800 (PST) Received: from a9-112.smtp-out.amazonses.com (a9-112.smtp-out.amazonses.com. [54.240.9.112]) by mx.google.com with ESMTP id 4si12666637qeq.17.2013.12.02.09.18.17 for ; Mon, 02 Dec 2013 09:18:17 -0800 (PST) Date: Mon, 2 Dec 2013 17:18:16 +0000 From: Christoph Lameter Subject: Re: netfilter: active obj WARN when cleaning up In-Reply-To: <20131202164039.GA19937@kroah.com> Message-ID: <00000142b4514eb5-2e8f675d-0ecc-423b-9906-58c5f383089b-000000@email.amazonses.com> References: <5294F27D.4000108@oracle.com> <20131126230709.GA10948@localhost> <20131127113939.GL16735@n2100.arm.linux.org.uk> <20131127133231.GO16735@n2100.arm.linux.org.uk> <20131127134015.GA6011@n2100.arm.linux.org.uk> <20131127233415.GB19270@kroah.com> <00000142b4282aaf-913f5e4c-314c-4351-9d24-615e66928157-000000@email.amazonses.com> <20131202164039.GA19937@kroah.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org List-ID: To: Greg KH Cc: Thomas Gleixner , Russell King - ARM Linux , Pablo Neira Ayuso , Sasha Levin , Patrick McHardy , kadlec@blackhole.kfki.hu, "David S. Miller" , netfilter-devel@vger.kernel.org, coreteam@netfilter.org, netdev@vger.kernel.org, LKML , linux-mm@kvack.org, Andrew Morton On Mon, 2 Dec 2013, Greg KH wrote: > On Mon, Dec 02, 2013 at 04:33:20PM +0000, Christoph Lameter wrote: > > On Wed, 27 Nov 2013, Greg KH wrote: > > > > > Just make the kobject "dynamic" instead of embedded in struct kmem_cache > > > and all will be fine. I can't believe this code has been broken for > > > this long. > > > > The slub code is was designed to use an embedded structure since we > > only get the kobj pointer passed to us from sysfs. If kobj is not > > embedded then how can we get from the sysfs object to the kmem_cache > > structure from the sysfs callbacks? Sysfs was designed to have embedded > > objects as far as I can recall. > > Yes, it's designed to have embedded objects, so then use it that way and > clean up the structure when the kobject goes away. Don't use a > different reference count for your structure than the one in the kobject > and think that all will be fine. We need our own reference count. So we just have to defer the release of the kmem_cache struct until the ->release callback is triggered. The put of the embedded kobject must be the last action on the kmem_cache structure which will then trigger release and that will trigger the kmem_cache_free(). -- 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/ . Don't email: email@kvack.org