linux-kernel - Re: [PATCH 2/2] media: qcom: camss: vfe: Fix registration sequencing bug

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: <2df8eeec-406d-4911-9c1b-1aafcc8be8d5@linaro.org>
Date: Mon, 16 Jun 2025 17:08:16 +0100
From: Bryan O'Donoghue <bryan.odonoghue@...aro.org>
To: Vladimir Zapolskiy <vladimir.zapolskiy@...aro.org>,
 Johan Hovold <johan@...nel.org>
Cc: Robert Foss <rfoss@...nel.org>, Todor Tomov <todor.too@...il.com>,
 Mauro Carvalho Chehab <mchehab@...nel.org>, Hans Verkuil
 <hverkuil@...all.nl>, Depeng Shao <quic_depengs@...cinc.com>,
 linux-media@...r.kernel.org, linux-arm-msm@...r.kernel.org,
 linux-kernel@...r.kernel.org, stable@...r.kernel.org,
 Johan Hovold <johan+linaro@...nel.org>
Subject: Re: [PATCH 2/2] media: qcom: camss: vfe: Fix registration sequencing
 bug

On 16/06/2025 16:00, Vladimir Zapolskiy wrote:
> Hi Bryan.
> 
> On 6/16/25 17:09, Bryan O'Donoghue wrote:
>> On 13/06/2025 10:13, Vladimir Zapolskiy wrote:
>>>
>>> Per se this concurrent execution shall not lead to the encountered bug,
>>
>> What does that mean ? Please re-read the commit log, the analysis is all
>> there.
> 
> The concurrent execution does not state a problem, moreover it's a feature
> of operating systems.

I don't quite understand what your objection is.

I'm informing the reader of the commit log that one function may execute 
in parallel to another function, this is not so with every function and 
is root-cause of the error.


>>> both an initialization of media entity pads by media_entity_pads_init()
>>> and a registration of a v4l2 devnode inside msm_video_register() are
>>> done under in a proper sequence, aren't they?
>>
>> No, I clearly haven't explained this clearly enough in the commit log.
>>
>> vfe0_rdi0 == /dev/video0 is complete. vfe0_rdi1 is not complete there is
>> no /dev/video1 in user-space.
> 
> Please let me ask for a few improvements to the commit message of the next
> version of the fix.
> 
> Te information like "vfe0_rdi0 == /dev/video0" etc. above vaguely assumes
> so much of the context
Sure but this is a _response_ email to you and you know what vfe0_rdi0 is.

The statement doesn't appear in the commit log.

---
bod