From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755548Ab3GAVx7 (ORCPT ); Mon, 1 Jul 2013 17:53:59 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:49847 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755100Ab3GAVx6 (ORCPT ); Mon, 1 Jul 2013 17:53:58 -0400 Date: Mon, 1 Jul 2013 14:53:56 -0700 From: Andrew Morton To: Tetsuo Handa Cc: cl@linux.com, glommer@parallels.com, penberg@kernel.org, linux-kernel@vger.kernel.org Subject: Re: [linux-next-20130422] Bug in SLAB? Message-Id: <20130701145356.f9c43875890d1aec90fe1ad9@linux-foundation.org> In-Reply-To: <201307020645.JGI86434.FFHOLOSFOtJVMQ@I-love.SAKURA.ne.jp> References: <201305040915.AID02071.FHVQJtOFOMOLSF@I-love.SAKURA.ne.jp> <0000013e7a18153d-4b59eaf6-0fcd-4eec-b357-31d3d40baa7d-000000@email.amazonses.com> <201305071938.DAC81273.HOSJOFFOQLtMFV@I-love.SAKURA.ne.jp> <0000013e7f651028-9a57bc30-4148-4aba-a0e6-737b83bf2458-000000@email.amazonses.com> <20130701130903.61459f57f4ba31e282065001@linux-foundation.org> <201307020645.JGI86434.FFHOLOSFOtJVMQ@I-love.SAKURA.ne.jp> X-Mailer: Sylpheed 3.2.0beta5 (GTK+ 2.24.10; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 2 Jul 2013 06:45:27 +0900 Tetsuo Handa wrote: > > > I've read through the thread trying to work out what the end-user > > impact of that fix is, but it's all clear as mud. It's possible that > > the end-user effect is `kernel locks up after printing "Booting the > > kernel"'. Or maybe not. > > > > And if the above patch does indeed fix something significant, we might > > need a -stable backport. > > > > Somebody needs this patch when debugging with CONFIG_LOCKDEP=y on > architectures with PAGE_SHIFT + MAX_ORDER > 26 . Well *why* do they need it? What happens without the patch? How would a person determine whether their kernel needs this patch? When this patch crosses Greg's desk for -stable inclusion he's going to wonder "why do users of -stable kernels need this", and you guys haven't told him! Grumble. Why is it so hard to get a simple and decent changelog for this patch? Look, I'll make this easier: : Subject: slab: fix init_lock_keys : : In 3.10 kernels with CONFIG_LOCKDEP=y on architectures with : PAGE_SHIFT + MAX_ORDER > 26 such as [architecture goes here], the kernel does : [x] when the user does [y]. : : init_lock_keys() goes too far in initializing values in kmalloc_caches : because it assumed that the size of the kmalloc array goes up to : MAX_ORDER. However, the size of the kmalloc array for SLAB may be : restricted due to increased page sizes or CONFIG_FORCE_MAX_ZONEORDER. : : Fix this by [z]. Please fill in the text within [].