linux-kernel - Re: 3.8-rc2: EFI framebuffer lock inversion...

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:	Thu, 3 Jan 2013 16:09:37 +0100
From:	Sedat Dilek <sedat.dilek@...il.com>
To:	Daniel J Blueman <daniel@...ra.org>
Cc:	alan@...rguk.ukuu.org.uk, linux-fbdev@...r.kernel.org,
	LKML <linux-kernel@...r.kernel.org>,
	Daniel Vetter <daniel.vetter@...ll.ch>,
	Dave Airlie <airlied@...il.com>
Subject: Re: 3.8-rc2: EFI framebuffer lock inversion...

On Thu, Jan 3, 2013 at 3:39 PM, Daniel J Blueman <daniel@...ra.org> wrote:
> On 3 January 2013 22:11, Sedat Dilek <sedat.dilek@...il.com> wrote:
>> Hi Daniel,
>>
>> just wanted to test the fb-fix [2] from Alan and followed the thread in [1].
>> Me is also working with i915 KMS.
>>
>> I looked at nouveau KMS driver and adapted the part for i915:
>>
>> drivers/gpu/drm/nouveau/nouveau_drm.c-200-      /* remove conflicting
>> drivers (vesafb, efifb etc) */
>> drivers/gpu/drm/nouveau/nouveau_drm.c:201:      aper = alloc_apertures(3);
>> drivers/gpu/drm/nouveau/nouveau_drm.c-202-      if (!aper)
>> drivers/gpu/drm/nouveau/nouveau_drm.c-203-              return -ENOMEM;
>>
>> Untested by me, feel free to test.
>>
>> Maybe some of the i915 and/or fb driver experts can comment on the problem.
>
> The structure array from alloc_apertures is just used for the PCI base
> address registers, so it's important here.
>
> I'll take a look at the efifb locking later.
>

That is the code part [1] I looked at.
Maybe the next lines with ap(er)->ranges || pci_resource_start() and
pci_resource_len() are missing?

I also looked at "include/linux/fb.h" but could not get wiser.
Also I can't say what the value "1" or "3" means in alloc_apertures().

Wouldn't it make sense to remove the conflicting fb-drivers globally
not in each affected DRM/KMS driver?
Just an idea.

- Sedat -

[1] http://git.kernel.org/?p=linux/kernel/git/torvalds/linux.git;a=blob;f=drivers/gpu/drm/nouveau/nouveau_drm.c;hb=refs/tags/v3.8-rc2#l192

> Thanks,
>   Daniel
> --
> Daniel J Blueman
--
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/