Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933410Ab3JOSLx (ORCPT ); Tue, 15 Oct 2013 14:11:53 -0400 Received: from mx1.redhat.com ([209.132.183.28]:26067 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932793Ab3JOSLw (ORCPT ); Tue, 15 Oct 2013 14:11:52 -0400 Date: Tue, 15 Oct 2013 14:11:42 -0400 From: Dave Jones To: sandeen@redhat.com, tytso@mit.edu, Linux Kernel Subject: Re: Patch "ext4: fix memory leak in xattr" has been added to the 3.0-stable tree Message-ID: <20131015181142.GA23581@redhat.com> Mail-Followup-To: Dave Jones , sandeen@redhat.com, tytso@mit.edu, Linux Kernel References: <13817826832984@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <13817826832984@kroah.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1830 Lines: 56 On Mon, Oct 14, 2013 at 01:31:23PM -0700, gregkh@linuxfoundation.org wrote: > If we take the 2nd retry path in ext4_expand_extra_isize_ea, we > potentionally return from the function without having freed these > allocations. If we don't do the return, we over-write the previous > allocation pointers, so we leak either way. > > Spotted with Coverity. > > [ Fixed by tytso to set is and bs to NULL after freeing these > pointers, in case in the retry loop we later end up triggering an > error causing a jump to cleanup, at which point we could have a double > free bug. -- Ted ] > > --- > fs/ext4/xattr.c | 2 ++ > 1 file changed, 2 insertions(+) > > --- a/fs/ext4/xattr.c > +++ b/fs/ext4/xattr.c > @@ -1271,6 +1271,8 @@ retry: > s_min_extra_isize) { > tried_min_extra_isize++; > new_extra_isize = s_min_extra_isize; > + kfree(is); is = NULL; > + kfree(bs); bs = NULL; > goto retry; > } Because this was different in my local tree I ended up looking it over again when I rebased. Do we also need the patch below ? Dave If we take the retry path here, we end up potentially overwriting bh, leaving it with an elevated reference count. Signed-off-by: Dave Jones diff --git a/fs/ext4/xattr.c b/fs/ext4/xattr.c index 03e9beb..1423c48 100644 --- a/fs/ext4/xattr.c +++ b/fs/ext4/xattr.c @@ -1352,6 +1352,7 @@ retry: new_extra_isize = s_min_extra_isize; kfree(is); is = NULL; kfree(bs); bs = NULL; + brelse(bh); goto retry; } error = -1; -- 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/