Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933057AbbFIMGM (ORCPT ); Tue, 9 Jun 2015 08:06:12 -0400 Received: from mail-pa0-f46.google.com ([209.85.220.46]:34005 "EHLO mail-pa0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932242AbbFIMFq (ORCPT ); Tue, 9 Jun 2015 08:05:46 -0400 From: Sergey Senozhatsky 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 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> X-Mailer: git-send-email 2.4.3.368.g7974889 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: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1291 Lines: 44 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 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/