Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753461Ab3EHWJf (ORCPT ); Wed, 8 May 2013 18:09:35 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:38156 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751996Ab3EHWJe (ORCPT ); Wed, 8 May 2013 18:09:34 -0400 Date: Wed, 8 May 2013 15:09:32 -0700 From: Andrew Morton To: Chris Mason Cc: Christoph Lameter , Pekka Enberg , Linus Torvalds , "linux-kernel@vger.kernel.org" , Tony Lindgren Subject: Re: [PATCH] Fix crash during slab init Message-Id: <20130508150932.e6ea333eb8e023940d15ac46@linux-foundation.org> In-Reply-To: <20130508195628.4271.97115@localhost.localdomain> References: <20130508003022.GS28721@atomide.com> <20130508042422.GU28721@atomide.com> <20130508181353.23991.17852@localhost.localdomain> <0000013e856463fa-9a895b58-ef76-42fa-a33d-778b89f97cf2-000000@email.amazonses.com> <20130508184817.4271.72594@localhost.localdomain> <0000013e85852607-fd84223c-112e-46b9-a60f-73d9597d90ac-000000@email.amazonses.com> <20130508195628.4271.97115@localhost.localdomain> 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 Content-Length: 3340 Lines: 84 On Wed, 8 May 2013 15:56:28 -0400 Chris Mason wrote: > Commit 8a965b3b introduced a regression that caused us to crash early > during boot. The commit was introducing ordering of slab creation, > making sure two odd-sized slabs were created after specific powers of > two sizes. > > But, if any of the power of two slabs were created earlier during boot, > slabs at index 1 or 2 might not get created at all. This patch makes > sure none of the slabs get skipped. > > Tony Lindgren bisected this down to the offending commit, which really > helped because bisect kept bringing me to almost but not quite this one. err, yes. Without your patch, current mainline does an ignominious faceplant on my test box. From: Chris Mason Subject: slab: fix crash during slab init Commit 8a965b3b ("mm, slab_common: Fix bootstrap creation of kmalloc caches") introduced a regression that caused us to crash early during boot. The commit was introducing ordering of slab creation, making sure two odd-sized slabs were created after specific powers of two sizes. But, if any of the power of two slabs were created earlier during boot, slabs at index 1 or 2 might not get created at all. This patch makes sure none of the slabs get skipped. Tony Lindgren bisected this down to the offending commit, which really helped because bisect kept bringing me to almost but not quite this one. Signed-off-by: Chris Mason Acked-by: Christoph Lameter Acked-by: Tony Lindgren Tested-by: Tetsuo Handa Cc: Pekka Enberg Tested-by: Andrew Morton Signed-off-by: Andrew Morton --- mm/slab_common.c | 20 ++++++++++---------- 1 file changed, 10 insertions(+), 10 deletions(-) diff -puN mm/slab_common.c~slab-fix-crash-during-slab-init mm/slab_common.c --- a/mm/slab_common.c~slab-fix-crash-during-slab-init +++ a/mm/slab_common.c @@ -446,18 +446,18 @@ void __init create_kmalloc_caches(unsign if (!kmalloc_caches[i]) { kmalloc_caches[i] = create_kmalloc_cache(NULL, 1 << i, flags); + } - /* - * Caches that are not of the two-to-the-power-of size. - * These have to be created immediately after the - * earlier power of two caches - */ - if (KMALLOC_MIN_SIZE <= 32 && !kmalloc_caches[1] && i == 6) - kmalloc_caches[1] = create_kmalloc_cache(NULL, 96, flags); + /* + * Caches that are not of the two-to-the-power-of size. + * These have to be created immediately after the + * earlier power of two caches + */ + if (KMALLOC_MIN_SIZE <= 32 && !kmalloc_caches[1] && i == 6) + kmalloc_caches[1] = create_kmalloc_cache(NULL, 96, flags); - if (KMALLOC_MIN_SIZE <= 64 && !kmalloc_caches[2] && i == 7) - kmalloc_caches[2] = create_kmalloc_cache(NULL, 192, flags); - } + if (KMALLOC_MIN_SIZE <= 64 && !kmalloc_caches[2] && i == 7) + kmalloc_caches[2] = create_kmalloc_cache(NULL, 192, flags); } /* Kmalloc array is now usable */ _ -- 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/