From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx0a-00082601.pphosted.com ([67.231.145.42]:31906 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751984AbaE0RTp (ORCPT ); Tue, 27 May 2014 13:19:45 -0400 Message-ID: <5384C9D9.9000705@fb.com> Date: Tue, 27 May 2014 13:22:33 -0400 From: Chris Mason MIME-Version: 1.0 To: Jeff Mahoney , linux-btrfs , David Sterba Subject: Re: [PATCH v4] btrfs: allocate raid type kobjects dynamically References: <5384C48D.7040707@suse.com> <5384C68C.507@fb.com> In-Reply-To: <5384C68C.507@fb.com> Content-Type: text/plain; charset="ISO-8859-1" Sender: linux-btrfs-owner@vger.kernel.org List-ID: On 05/27/2014 01:08 PM, Chris Mason wrote: > On 05/27/2014 12:59 PM, Jeff Mahoney wrote: >> We are currently allocating space_info objects in an array when we >> allocate space_info. When a user does something like: >> >> # btrfs balance start -mconvert=raid1 -dconvert=raid1 /mnt >> # btrfs balance start -mconvert=single -dconvert=single /mnt -f >> # btrfs balance start -mconvert=raid1 -dconvert=raid1 / >> >> We can end up with memory corruption since the kobject hasn't >> been reinitialized properly and the name pointer was left set. >> >> The rationale behind allocating them statically was to avoid >> creating a separate kobject container that just contained the >> raid type. It used the index in the array to determine the index. >> >> Ultimately, though, this wastes more memory than it saves in all >> but the most complex scenarios and introduces kobject lifetime >> questions. >> >> This patch allocates the kobjects dynamically instead. Note that >> we also remove the kobject_get/put of the parent kobject since >> kobject_add and kobject_del do that internally. >> >> Signed-off-by: Jeff Mahoney > > Lets see how smart patchwork is: > > Reported-by:David Sterba For future reference, not that smart. -chris