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From: Paul Menzel <pmenzel@molgen.mpg.de>
To: Kees Cook <keescook@chromium.org>
Cc: "Mazin Rezk" <mnrzk@protonmail.com>,
	linux-kernel@vger.kernel.org, amd-gfx@lists.freedesktop.org,
	dri-devel@lists.freedesktop.org,
	"Andrew Morton" <akpm@linux-foundation.org>,
	"Christian König" <christian.koenig@amd.com>,
	"Harry Wentland" <Harry.Wentland@amd.com>,
	"Nicholas Kazlauskas" <nicholas.kazlauskas@amd.com>,
	sunpeng.li@amd.com,
	"Alexander Deucher" <Alexander.Deucher@amd.com>,
	1i5t5.duncan@cox.net, mphantomx@yahoo.com.br,
	regressions@leemhuis.info, anthony.ruhier@gmail.com
Subject: Re: [PATCH] amdgpu_dm: fix nonblocking atomic commit use-after-free
Date: Fri, 24 Jul 2020 23:19:59 +0200	[thread overview]
Message-ID: <3c92db94-3b62-a70b-8ace-f5e34e8f268f@molgen.mpg.de> (raw)
In-Reply-To: <202007241016.922B094AAA@keescook>


Dear Kees,


Am 24.07.20 um 19:33 schrieb Kees Cook:
> On Fri, Jul 24, 2020 at 09:45:18AM +0200, Paul Menzel wrote:
>> Am 24.07.20 um 00:32 schrieb Kees Cook:
>>> On Thu, Jul 23, 2020 at 09:10:15PM +0000, Mazin Rezk wrote:
>> As Linux 5.8-rc7 is going to be released this Sunday, I wonder, if commit
>> 3202fa62f ("slub: relocate freelist pointer to middle of object") should be
>> reverted for now to fix the regression for the users according to Linux’ no
>> regression policy. Once the AMDGPU/DRM driver issue is fixed, it can be
>> reapplied. I know it’s not optimal, but as some testing is going to be
>> involved for the fix, I’d argue it’s the best option for the users.
> 
> Well, the SLUB defense was already released in v5.7, so I'm not sure it
> really helps for amdgpu_dm users seeing it there too.

In my opinion, it would help, as the stable release could pick up the 
revert, ones it’s in Linus’ master branch.

> There was a fix to disable the async path for this driver that worked
> around the bug too, yes? That seems like a safer and more focused
> change that doesn't revert the SLUB defense for all users, and would
> actually provide a complete, I think, workaround whereas reverting
> the SLUB change means the race still exists. For example, it would be
> hit with slab poisoning, etc.

I do not know. If there is such a fix, that would be great. But if you 
do not know, how should a normal user? ;-)


Kind regards,

Paul


Kind regards,

Paul

  reply	other threads:[~2020-07-24 21:20 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-23 21:10 [PATCH] amdgpu_dm: fix nonblocking atomic commit use-after-free Mazin Rezk
2020-07-23 22:16 ` Kazlauskas, Nicholas
2020-07-23 22:57   ` Mazin Rezk
2020-07-24 21:09     ` Mazin Rezk
2020-07-23 22:32 ` Kees Cook
2020-07-23 22:58   ` Mazin Rezk
2020-07-24  7:26     ` Christian König
2020-07-24  7:45   ` Paul Menzel
2020-07-24 17:33     ` Kees Cook
2020-07-24 21:19       ` Paul Menzel [this message]
2020-07-25  3:03         ` Mazin Rezk
2020-07-25  4:59           ` Duncan
2020-07-25  5:20             ` Mazin Rezk
2020-07-28  9:22               ` Paul Menzel
2020-07-28 17:07                 ` Kazlauskas, Nicholas
2020-07-28 21:58                   ` daniel

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