linux-kernel - Re: [PATCH] staging: media: atomisp: Fix premature setting of HMM_BO_DEVICE

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]

Message-ID: <CAGn2d8NBEwWm0mQ0YQ3KZ+V1Zon84zusfsQQV2foVmUTBAzEAQ@mail.gmail.com>
Date: Tue, 1 Jul 2025 18:45:15 +0300
From: Abdelrahman Fekry <abdelrahmanfekry375@...il.com>
To: Hans de Goede <hansg@...nel.org>
Cc: Andy Shevchenko <andriy.shevchenko@...el.com>, 
	Andy Shevchenko <andy.shevchenko@...il.com>, andy@...nel.org, hdegoede@...hat.com, 
	mchehab@...nel.org, sakari.ailus@...ux.intel.com, gregkh@...uxfoundation.org, 
	linux-kernel-mentees@...ts.linux.dev, linux-kernel@...r.kernel.org, 
	linux-media@...r.kernel.org, linux-staging@...ts.linux.dev, 
	skhan@...uxfoundation.com, dan.carpenter@...aro.org
Subject: Re: [PATCH] staging: media: atomisp: Fix premature setting of
 HMM_BO_DEVICE_INITED flag

Hi Hans,

On Tue, Jul 1, 2025 at 4:54 PM Hans de Goede <hansg@...nel.org> wrote:
>
> Hi,
>
> On 1-Jul-25 2:45 PM, Andy Shevchenko wrote:
> > On Tue, Jul 01, 2025 at 02:58:43PM +0300, Abdelrahman Fekry wrote:
> >> Hello Andy,
> >> On Sat, Jun 28, 2025 at 10:52 PM Andy Shevchenko
> >> <andy.shevchenko@...il.com> wrote:
> >>> On Sat, Jun 28, 2025 at 8:26 AM Abdelrahman Fekry
> >>> <abdelrahmanfekry375@...il.com> wrote:
> >
> >>>> The HMM_BO_DEVICE_INITED flag was being set in hmm_bo_device_init()
> >>>> before key initialization steps like kmem_cache_create(),
> >>>> kmem_cache_alloc(), and __bo_init().
> >>>>
> >>>> This means that if any of these steps fail, the flag remains set,
> >>>> misleading other parts of the driver (e.g. hmm_bo_alloc())
> >>>> into thinking the device is initialized. This could lead
> >>>> to undefined behavior or invalid memory use.
> >>>
> >>> Nice. Can you make some fault injection (temporary by modifying the
> >>> code to always fail, for example) and actually prove this in practice?
> >>> If so, the few (important) lines from the given Oops would be nice to
> >>> have here.
> >
> >> I have been trying to test it without having any intel atomisp
> >> hardware and failed continuously, do you have any tips or maybe some
> >> resources on how i can test this driver.
> >
> > So, the easiest way as I can see it is to ask people who possess the HW to
> > test, but you need to provide a testing patch (which can be applied on top
> > of this one, for example).
>
> I don't think it is worth testing the error path here,
> the old code is obviously wrong.
>
> What is interesting here is to see if the extra call to hmm_init()
> in __hmm_alloc() is necessary at all.
>
i think its redundant because in all scenarios hmm_init() should
be called before hmm_alloc()

> And obviously hmm_init() needs to propagate the error return
> from hmm_bo_init() right away instead of continuing if nothing
> was wrong and then only returning the error at the end.
>
> So it seems that there plenty of cleanup to do around this
> without needing error injection to test all paths.
>
> Actually I'm pretty sure that there will be quite a few
> error-handling paths with bugs in the atomisp code given
> its overall quality. But lets clean things up first, that
> should make addressing any such cases easier.
>
I totally agree with this , i have submitted a patch that cleans the
custom sysfs atrributes
as you suggested as a beginning , the patch got reviewed by andy and dan
here is the link
https://lore.kernel.org/all/20250627100604.29061-1-abdelrahmanfekry375@gmail.com/

What do you think I should work on next after these two patches, do
you have any suggestions?

> Regards,
>
> Hans
>
Best Regards,
Abdelrahman Fekry