From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pd0-f175.google.com (mail-pd0-f175.google.com [209.85.192.175]) by kanga.kvack.org (Postfix) with ESMTP id 3BB086B0102 for ; Wed, 6 Nov 2013 16:16:13 -0500 (EST) Received: by mail-pd0-f175.google.com with SMTP id g10so72810pdj.34 for ; Wed, 06 Nov 2013 13:16:12 -0800 (PST) Received: from psmtp.com ([74.125.245.183]) by mx.google.com with SMTP id mi5si418535pab.280.2013.11.06.13.16.10 for ; Wed, 06 Nov 2013 13:16:11 -0800 (PST) Date: Wed, 6 Nov 2013 22:16:04 +0100 From: Andreas Herrmann Subject: Re: [PATCH] mm/slub: Switch slub_debug kernel option to early_param to avoid boot panic Message-ID: <20131106211604.GM5661@alberich> References: <20131106184529.GB5661@alberich> <000001422ed8406b-14bef091-eee0-4e0e-bcdd-a8909c605910-000000@email.amazonses.com> <20131106195417.GK5661@alberich> <20131106203429.GL5661@alberich> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20131106203429.GL5661@alberich> Sender: owner-linux-mm@kvack.org List-ID: To: Christoph Lameter Cc: Pekka Enberg , Matt Mackall , "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" On Wed, Nov 06, 2013 at 09:34:29PM +0100, Andreas Herrmann wrote: > On Wed, Nov 06, 2013 at 08:54:17PM +0100, Andreas Herrmann wrote: > > On Wed, Nov 06, 2013 at 02:16:33PM -0500, Christoph Lameter wrote: > > > On Wed, 6 Nov 2013, Andreas Herrmann wrote: > > > > > > > When I've used slub_debug kernel option (e.g. > > > > "slub_debug=,skbuff_fclone_cache" or similar) on a debug session I've > > > > seen a panic like: > > > > > > Hmmm.. That looks like its due to some slabs not having names > > > during early boot. kmem_cache_flags is called with NULL as a parameter. > > > > That's because the slub_debug parameter is not evaluated before > > kmem_cache_flags is called. > > > > Older kernels didn't show this problem. I think the sequence of those > > calls has changed. Not sure what patch set has made that change. > > Please ignore this comment. > I revisisted the code and of course you are right. > Hmm, now wondering why my patch covered the panic. Arrgh, my patch changed slub_debug_slabs to be NULL. That is why the panic didn't happen. Would be nice, if your patch is pushed upstream asap. Thanks, Andreas -- 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