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Message-ID: <55c336a4-b268-d2d3-47f3-213300e4e623@baylibre.com>
Date:   Wed, 19 Jul 2023 12:17:55 +0200
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Subject: Re: [RESEND PATCH v2] media: mtk-jpeg: Fix use after free bug due to
 uncanceled work
To:     Zheng Hacker <hackerzheng666@gmail.com>
Cc:     Zheng Wang <zyytlz.wz@163.com>, Kyrie.Wu@mediatek.com,
        bin.liu@mediatek.com, mchehab@kernel.org, matthias.bgg@gmail.com,
        angelogioacchino.delregno@collabora.com,
        linux-media@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org,
        linux-mediatek@lists.infradead.org, Irui.Wang@mediatek.com,
        security@kernel.org, 1395428693sheep@gmail.com,
        alex000young@gmail.com
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From:   Alexandre Mergnat <amergnat@baylibre.com>
In-Reply-To: <CAJedcCyKv-hdDhWcogDZrC-kY6qtO-H1fDYqjTXMJvCR19MxYg@mail.gmail.com>
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On 18/07/2023 05:07, Zheng Hacker wrote:
> Friendly ping
> 
> Zheng Hacker <hackerzheng666@gmail.com> 于2023年7月16日周日 00:08写道：
>>
>> Hi,
>>
>> This issue has not been resolved for a long time. Is there anyone who can help?
>>
>> Best regards,
>> Zheng
>>
>> Alexandre Mergnat <amergnat@baylibre.com> 于2023年7月7日周五 22:11写道：
>>>
>>>
>>>
>>> On 07/07/2023 11:24, Zheng Wang wrote:
>>>> In mtk_jpeg_probe, &jpeg->job_timeout_work is bound with
>>>> mtk_jpeg_job_timeout_work. Then mtk_jpeg_dec_device_run
>>>> and mtk_jpeg_enc_device_run may be called to start the
>>>> work.
>>>> If we remove the module which will call mtk_jpeg_remove
>>>> to make cleanup, there may be a unfinished work. The
>>>> possible sequence is as follows, which will cause a
>>>> typical UAF bug.
>>>>
>>>> Fix it by canceling the work before cleanup in the mtk_jpeg_remove
>>>>
>>>> CPU0                  CPU1
>>>>
>>>>                       |mtk_jpeg_job_timeout_work
>>>> mtk_jpeg_remove     |
>>>>     v4l2_m2m_release  |
>>>>       kfree(m2m_dev); |
>>>>                       |
>>>>                       | v4l2_m2m_get_curr_priv
>>>>                       |   m2m_dev->curr_ctx //use
>>>
>>> Reviewed-by: Alexandre Mergnat <amergnat@baylibre.com>
>>>
>>> --
>>> Regards,
>>> Alexandre

Hi Zheng,

If you asking me to merge patch, sorry but I can't, I'm just a reviewer. 
I invite you to ping the maintainers directly:

Bin Liu <bin.liu@mediatek.com> (supporter:MEDIATEK JPEG DRIVER)
Mauro Carvalho Chehab <mchehab@kernel.org> (maintainer:MEDIA INPUT 
INFRASTRUCTURE (V4L/DVB))
Matthias Brugger <matthias.bgg@gmail.com> (maintainer:ARM/Mediatek SoC 
support)

Otherwise, I misunderstood what you asking me. If so, can you rephrase 
your question please?

-- 
Regards,
Alexandre