linux-kernel - Re: [rfc][patch] mm: half-fix page tail zeroing on write problem

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Date:	Fri, 2 Feb 2007 08:21:33 +0100
From:	Nick Piggin <npiggin@...e.de>
To:	Neil Brown <neilb@...e.de>
Cc:	Linux Memory Management List <linux-mm@...ck.org>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [rfc][patch] mm: half-fix page tail zeroing on write problem

On Fri, Feb 02, 2007 at 05:29:06PM +1100, Neil Brown wrote:
> On Friday February 2, npiggin@...e.de wrote:
> > Hi,
> > 
> > For no important reason, I've again looked at those zeroing patches that
> > Neil did a while back. I've always thought that a simple
> > `write(fd, NULL, size)` would cause the same sorts of problems.
> 
> Yeh, but who in their right mind would do that???
> Oh, you did :-)

Well that's the test-case. Obviously not many people do it, but that's
all the more reason to be careful about correct behaviour.

> I cannot see why you make a change to fault_in_pages_writeable.  Is it
> just for symmetry?

Yes.

> For the rest, it certainly makes sense to return an early -EFAULT if
> you cannot fault in the page.

I think so.

Thanks,
Nick
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/