From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-f47.google.com (mail-pa0-f47.google.com [209.85.220.47]) by kanga.kvack.org (Postfix) with ESMTP id 0A6576B006C for ; Tue, 9 Jun 2015 08:05:47 -0400 (EDT) Received: by pacyx8 with SMTP id yx8so12609671pac.2 for ; Tue, 09 Jun 2015 05:05:46 -0700 (PDT) Received: from mail-pa0-x236.google.com (mail-pa0-x236.google.com. [2607:f8b0:400e:c03::236]) by mx.google.com with ESMTPS id ai4si8638158pbc.176.2015.06.09.05.05.46 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 09 Jun 2015 05:05:46 -0700 (PDT) Received: by pabqy3 with SMTP id qy3so12556455pab.3 for ; Tue, 09 Jun 2015 05:05:46 -0700 (PDT) From: Sergey Senozhatsky Subject: [RFC][PATCH 1/5] mm/slab_common: allow NULL cache pointer in kmem_cache_destroy() Date: Tue, 9 Jun 2015 21:04:49 +0900 Message-Id: <1433851493-23685-2-git-send-email-sergey.senozhatsky@gmail.com> In-Reply-To: <1433851493-23685-1-git-send-email-sergey.senozhatsky@gmail.com> References: <1433851493-23685-1-git-send-email-sergey.senozhatsky@gmail.com> Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton Cc: Minchan Kim , Christoph Lameter , Pekka Enberg , Joonsoo Kim , Michal Hocko , David Rientjes , linux-mm@kvack.org, linux-kernel@vger.kernel.org, sergey.senozhatsky.work@gmail.com, Sergey Senozhatsky kmem_cache_destroy() does not tolerate a NULL kmem_cache pointer argument and performs a NULL-pointer dereference. This requires additional attention and effort from developers/reviewers and forces all kmem_cache_destroy() callers (200+ as of 4.1) to do a NULL check if (cache) kmem_cache_destroy(cache); Or, otherwise, be invalid kmem_cache_destroy() users. Tweak kmem_cache_destroy() and NULL-check the pointer there. Proposed by Andrew Morton. Signed-off-by: Sergey Senozhatsky Reported-by: Andrew Morton LKML-reference: https://lkml.org/lkml/2015/6/8/583 --- mm/slab_common.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/mm/slab_common.c b/mm/slab_common.c index 8873985..ea69b13 100644 --- a/mm/slab_common.c +++ b/mm/slab_common.c @@ -641,6 +641,9 @@ void kmem_cache_destroy(struct kmem_cache *s) bool need_rcu_barrier = false; bool busy = false; + if (unlikely(!s)) + return; + BUG_ON(!is_root_cache(s)); get_online_cpus(); -- 2.4.3.368.g7974889 -- 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