From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756129AbbFQXPK (ORCPT ); Wed, 17 Jun 2015 19:15:10 -0400 Received: from mail-ig0-f178.google.com ([209.85.213.178]:35936 "EHLO mail-ig0-f178.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752593AbbFQXPB (ORCPT ); Wed, 17 Jun 2015 19:15:01 -0400 Date: Wed, 17 Jun 2015 16:14:59 -0700 (PDT) From: David Rientjes X-X-Sender: rientjes@chino.kir.corp.google.com To: Sergey Senozhatsky cc: Andrew Morton , Minchan Kim , Christoph Lameter , Pekka Enberg , Joonsoo Kim , Michal Hocko , linux-mm@kvack.org, linux-kernel@vger.kernel.org, sergey.senozhatsky.work@gmail.com Subject: Re: [RFC][PATCH 1/5] mm/slab_common: allow NULL cache pointer in kmem_cache_destroy() In-Reply-To: <1433851493-23685-2-git-send-email-sergey.senozhatsky@gmail.com> Message-ID: References: <1433851493-23685-1-git-send-email-sergey.senozhatsky@gmail.com> <1433851493-23685-2-git-send-email-sergey.senozhatsky@gmail.com> User-Agent: Alpine 2.10 (DEB 1266 2009-07-14) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 9 Jun 2015, Sergey Senozhatsky wrote: > 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 Acked-by: David Rientjes kmem_cache_destroy() isn't a fastpath, this is long overdue. Now where's the patch to remove the NULL checks from the callers? ;)