From mboxrd@z Thu Jan 1 00:00:00 1970 From: Linus Torvalds Subject: Re: [PATCH 2/2] add f_flags to struct statfs(64) Date: Wed, 7 Jul 2010 11:06:29 -0700 Message-ID: References: <20100707165325.GB12557@lst.de> <4C34B53A.6060408@redhat.com> <20100707173311.GA14608@lst.de> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: Christoph Hellwig , drepper@redhat.com, viro@zeniv.linux.org.uk, linux-fsdevel@vger.kernel.org To: Miklos Szeredi Return-path: Received: from smtp1.linux-foundation.org ([140.211.169.13]:50723 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754669Ab0GGSGf convert rfc822-to-8bit (ORCPT ); Wed, 7 Jul 2010 14:06:35 -0400 Received: from mail-px0-f174.google.com (mail-px0-f174.google.com [209.85.212.174]) (authenticated bits=0) by smtp1.linux-foundation.org (8.14.2/8.13.5/Debian-3ubuntu1.1) with ESMTP id o67I6Z52009139 (version=TLSv1/SSLv3 cipher=RC4-MD5 bits=128 verify=FAIL) for ; Wed, 7 Jul 2010 11:06:35 -0700 Received: by pxi14 with SMTP id 14so2778680pxi.19 for ; Wed, 07 Jul 2010 11:06:30 -0700 (PDT) In-Reply-To: Sender: linux-fsdevel-owner@vger.kernel.org List-ID: On Wed, Jul 7, 2010 at 10:55 AM, Miklos Szeredi wro= te: > > 1.0 =A0 =A0 - doesn't touch spare fields > 1.2.13 =A0- doesn't touch spare fields > 2.0.40 =A0- copies spare fields from uninitialized kernel stack > 2.2.26 =A0- copies spare fields from uninitialized kernel stack > 2.4 onward - zeroes spare fields I think at least some of the compat_ functions don't zero the fields even now (the kstatfs struct, yes, but then don't copy them to user space). As to any uninitialized kernel stack copying, we really don't even want to care. Not only are those ancient kernels (and nobody is going to upgrade glibc if they haven't upgraded the kernel), but it's clearly a kernel bug, and the potential "wrong f_flags" problem is way smaller than the "leaks kernel data" problem. Not that anybody even uses statvfs(). The first google hit on statvfs() I found was somebody implementing a compatibility statfs() on top of it, and obviously ignoring any f_flags field. So the only reason this is even an issue in the first place is just the tbench performance issue. In other words: NOBODY CARES. It's that simple. So please, guys - just do the obvious thing, or shut the h*ll up about it. There is _no_ reason to care in the least about any of this. Linus -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel= " in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html