Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750922Ab3CEFEs (ORCPT ); Tue, 5 Mar 2013 00:04:48 -0500 Received: from mail-vb0-f51.google.com ([209.85.212.51]:53734 "EHLO mail-vb0-f51.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750729Ab3CEFEq (ORCPT ); Tue, 5 Mar 2013 00:04:46 -0500 MIME-Version: 1.0 In-Reply-To: <51356BD8.4040408@cn.fujitsu.com> References: <1362454007-353-1-git-send-email-ebiederm@xmission.com> <51356BD8.4040408@cn.fujitsu.com> Date: Tue, 5 Mar 2013 02:04:45 -0300 Message-ID: Subject: Re: [PATCH 1/1] kernel/pid_namespace.c: Fixing a lack of cleanup (Probable resources leak). From: Raphael S Carvalho To: Gao feng Cc: Andrew Morton , Oleg Nesterov , Cyrill Gorcunov , Serge Hallyn , linux-kernel@vger.kernel.org Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1888 Lines: 43 On Tue, Mar 5, 2013 at 12:51 AM, Gao feng wrote: > On 2013/03/05 11:26, Eric W. Biederman wrote: >> From: Raphael S.Carvalho >> >> Starting point: create_pid_namespace() >> >> Suppose create_pid_cachep() was executed sucessfully, thus: >> pcache was allocated by kmalloc(). >> cachep received a cache created by kmem_cache_create(). >> and pcache->list was added to the list pid_caches_lh. >> >> So what would happen if proc_alloc_inum() returns an error? >> The resources allocated by create_pid_namespace() would be deallocated! >> How about those resources allocated by create_pid_cachep()? >> By knowing that, I created this patch in order to fix that! >> >> Signed-off-by: Raphael S.Carvalho >> --- > > Actually I noticed this problem and I think it is not a BUG. > Since the pid_cache is created for all pid namespace which have the same level. > Even this pid namespace is failed to create, the pid_cache will not be leaked, Other > pid namespace which has the same level will use the pid_cache and no need to > allocate it again. In other words, the pid_cache for every level pid namespace will > only be created once. > > I also think this patch add a bug,because there may be other pid namespace's pid_cachep > points to the same pid_cache which will be free at the by label out_free_cachep. > Yeah, I found the snippet of code which searches for the pcache with the same level. 46 list_for_each_entry(pcache, &pid_caches_lh, list) 47 if (pcache->nr_ids == nr_ids) 48 goto out; Regards, Raphael S.Carvalho -- 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/