linux-kernel - Re: [Intel-gfx] [PATCH] intel-gtt: fix memory corruption with GM965 and >4GB RAM

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

Date:	Sat, 26 Feb 2011 00:05:27 +0100
From:	Daniel Vetter <daniel@...ll.ch>
To:	Chris Wilson <chris@...is-wilson.co.uk>
Cc:	Jan Niehusmann <jan@...dor.com>, intel-gfx@...ts.freedesktop.org,
	linux-kernel@...r.kernel.org
Subject: Re: [Intel-gfx] [PATCH] intel-gtt: fix memory corruption with
 GM965 and >4GB RAM

On Fri, Feb 25, 2011 at 10:18:16PM +0000, Chris Wilson wrote:
> So, I'm happy to use your patch to workaround the known erratum. I just
> wish I had an explanation as to what is actually causing the corruption.
> What I want to make sure is that we don't paper over a real bug by
> thinking it is yet another silicon issue.

Actually, on style points I prefer your patch: The hw status page is
allocated with drm_pci_alloc which calls dma_alloc_coherent, so setting
the coherent mask is sufficient. The dma mask set in the gtt is
essentially useless, because we call get_user_pages on everything anyway
(in gem - iirc agp uses it). I just think it's confusing to limit the
general dma mask and continue to happily map pages above 4G.

Cheers, Daniel
-- 
Daniel Vetter
Mail: daniel@...ll.ch
Mobile: +41 (0)79 365 57 48
--
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/