From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wr0-f199.google.com (mail-wr0-f199.google.com [209.85.128.199]) by kanga.kvack.org (Postfix) with ESMTP id 035D46B0279 for ; Fri, 7 Jul 2017 16:23:56 -0400 (EDT) Received: by mail-wr0-f199.google.com with SMTP id u110so10392554wrb.14 for ; Fri, 07 Jul 2017 13:23:55 -0700 (PDT) Received: from mail.linuxfoundation.org (mail.linuxfoundation.org. [140.211.169.12]) by mx.google.com with ESMTPS id g11si295455wmg.151.2017.07.07.13.23.54 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 07 Jul 2017 13:23:54 -0700 (PDT) Date: Fri, 7 Jul 2017 13:23:51 -0700 From: Andrew Morton Subject: Re: [PATCH] slub: make sure struct kmem_cache_node is initialized before publication Message-Id: <20170707132351.4f10cd778fc5eb58e9cc5513@linux-foundation.org> In-Reply-To: <20170707083408.40410-1-glider@google.com> References: <20170707083408.40410-1-glider@google.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Alexander Potapenko Cc: dvyukov@google.com, kcc@google.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Pekka Enberg , David Rientjes , Christoph Lameter , Joonsoo Kim On Fri, 7 Jul 2017 10:34:08 +0200 Alexander Potapenko wrote: > --- a/mm/slub.c > +++ b/mm/slub.c > @@ -3389,8 +3389,8 @@ static int init_kmem_cache_nodes(struct kmem_cache *s) > return 0; > } > > - s->node[node] = n; > init_kmem_cache_node(n); > + s->node[node] = n; > } > return 1; > } If this matters then I have bad feelings about free_kmem_cache_nodes(): static void free_kmem_cache_nodes(struct kmem_cache *s) { int node; struct kmem_cache_node *n; for_each_kmem_cache_node(s, node, n) { kmem_cache_free(kmem_cache_node, n); s->node[node] = NULL; } } Inviting a use-after-free? I guess not, as there should be no way to look up these items at this stage. Could the slab maintainers please take a look at these and also have a think about Alexander's READ_ONCE/WRITE_ONCE question? -- 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