Re: [PATCH 009/190] Revert "media: s5p-mfc: Fix a reference count leak"

Hans Verkuil
2021-04-23T08:10:29Z

On 23/04/2021 10:07, Mauro Carvalho Chehab wrote:
> Em Fri, 23 Apr 2021 09:10:32 +0200
> Greg Kroah-Hartman <gregkh@linuxfoundation.org> escreveu:
>
>> On Fri, Apr 23, 2021 at 09:04:27AM +0200, Krzysztof Kozlowski wrote:
>>> On 21/04/2021 14:58, Greg Kroah-Hartman wrote:
>>>> This reverts commit 78741ce98c2e36188e2343434406b0e0bc50b0e7.
>>>>
>>>> Commits from @umn.edu addresses have been found to be submitted in "bad
>>>> faith" to try to test the kernel community's ability to review "known
>>>> malicious" changes. The result of these submissions can be found in a
>>>> paper published at the 42nd IEEE Symposium on Security and Privacy
>>>> entitled, "Open Source Insecurity: Stealthily Introducing
>>>> Vulnerabilities via Hypocrite Commits" written by Qiushi Wu (University
>>>> of Minnesota) and Kangjie Lu (University of Minnesota).
>>>>
>>>> Because of this, all submissions from this group must be reverted from
>>>> the kernel tree and will need to be re-reviewed again to determine if
>>>> they actually are a valid fix. Until that work is complete, remove this
>>>> change to ensure that no problems are being introduced into the
>>>> codebase.
>>>>
>>>> Cc: Qiushi Wu <wu000273@umn.edu>
>>>> Cc: Hans Verkuil <hverkuil-cisco@xs4all.nl>
>>>> Cc: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
>>>> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
>>>> ---
>>>> drivers/media/platform/s5p-mfc/s5p_mfc_pm.c | 4 +---
>>>> 1 file changed, 1 insertion(+), 3 deletions(-)
>>>>
>>>
>>> This looks like a good commit but should be done now in a different way
>>> - using pm_runtime_resume_and_get(). Therefore I am fine with revert
>>> and I can submit later better fix.
>>
>> Great, thanks for letting me know, I can have someone work on the
>> "better fix" at the same time.
>
> IMO, it is better to keep the fix. I mean, there's no reason to
> revert a fix that it is known to be good.
>
> The "better fix" patch can be produced anytime. A simple coccinelle
> ruleset can replace patterns like:
>
> ret = pm_runtime_get_sync(pm->device);
> if (ret < 0) {
> pm_runtime_put_noidle(pm->device);
> return ret;
> }
>
> and the broken pattern:
>
> ret = pm_runtime_get_sync(pm->device);
> if (ret < 0)
> return ret;
>
> to:
>
> ret = pm_runtime_resume_and_get(pm->device);
> if (ret < 0)
> return ret;

That's my preference as well.

Hans

>
> Regards,
> Mauro
>