Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
	id S1756428AbaLICVl (ORCPT <rfc822;w@1wt.eu>);
	Mon, 8 Dec 2014 21:21:41 -0500
Received: from mta-out1.inet.fi ([62.71.2.195]:60276 "EHLO kirsi1.inet.fi"
	rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP
	id S1755745AbaLICVk (ORCPT <rfc822;linux-kernel@vger.kernel.org>);
	Mon, 8 Dec 2014 21:21:40 -0500
Date: Tue, 9 Dec 2014 04:21:35 +0200
From: "Kirill A. Shutemov" <kirill@shutemov.name>
To: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        linux-fsdevel <linux-fsdevel@vger.kernel.org>,
        Network Development <netdev@vger.kernel.org>
Subject: Re: [RFC][PATCHES] iov_iter.c rewrite
Message-ID: <20141209022135.GA992@node.dhcp.inet.fi>
References: <20141208164650.GB29028@node.dhcp.inet.fi>
 <20141208175805.GB22149@ZenIV.linux.org.uk>
 <20141208180824.GC22149@ZenIV.linux.org.uk>
 <CA+55aFxwrH4vsyw2ix=HqDK9Z=fw98xtOL8=57prm8qgVmAFfA@mail.gmail.com>
 <20141208182012.GE22149@ZenIV.linux.org.uk>
 <CA+55aFxrrTV-xBbvEzVKsXRVKyvZhQZj-6BNDpTsG4J5k6CJEg@mail.gmail.com>
 <20141208184632.GG22149@ZenIV.linux.org.uk>
 <CA+55aFyh0cV+ztK47mu1QN6aF4VvPE1V5zF7_X2TdYxZ38zZRA@mail.gmail.com>
 <20141208192816.GH22149@ZenIV.linux.org.uk>
 <20141209015651.GI22149@ZenIV.linux.org.uk>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20141209015651.GI22149@ZenIV.linux.org.uk>
User-Agent: Mutt/1.5.23.1 (2014-03-12)
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On Tue, Dec 09, 2014 at 01:56:51AM +0000, Al Viro wrote:
> On Mon, Dec 08, 2014 at 07:28:17PM +0000, Al Viro wrote:
> > On Mon, Dec 08, 2014 at 10:57:31AM -0800, Linus Torvalds wrote:
> > > So the whole "get_page()" thing is broken. Iterating over pages in a
> > > KVEC is simply wrong, wrong, wrong. It needs to fail.
> > 
> > Well, _that_ is easy to do, of course...  E.g. by replacing that thing in
> > iov_iter_get_pages()/iov_iter_get_pages_alloc() with ({ return -EFAULT; })
> > will do it.
> 
> OK, folded and pushed (i.e. in vfs.git#iov_iter and vfs.git#for-next).
> Matches earlier behaviour; oops reproducer is easy -
> 
> dd if=/dev/zero of=foo.ko bs=4096 count=1
> cat >a.c <<'EOF'
> #define _GNU_SOURCE
> #include <unistd.h>
> #include <fcntl.h>
> #include <sys/stat.h>
> #include <sys/syscall.h>
> main()
> {
>         int fd = open("foo.ko", 00040000);
>         syscall(__NR_finit_module, fd, "", 0);
> }
> EOF
> gcc a.c
> strace ./a.out
> 
> Correct behaviour (both the mainline and this series with fixes folded):
> open("foo.ko", O_RDONLY|O_DIRECT)       = 3
> finit_module(3, "", 0)                  = -1 EFAULT (Bad address)
> Incorrect one:
> open("foo.ko", O_RDONLY|O_DIRECT)       = 3
> finit_module(3, "", 0 <unfinished ...>
> +++ killed by SIGKILL +++
> Killed
> 
> with that oops reproduced.  Not sure if it's a proper LTP or xfstests fodder,
> but anyway, here it is.
> 
> Incremental from previous for-next is

Works for me.

-- 
 Kirill A. Shutemov
--
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/