linux-kernel - Re: [PATCH] media: sti: Fix reference count leaks

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Date:   Wed, 21 Apr 2021 15:29:21 +0200
From:   Krzysztof Kozlowski <krzk@...nel.org>
To:     Hans Verkuil <hverkuil@...all.nl>
Cc:     Jean-Christophe Trotin <jean-christophe.trotin@...com>,
        wu000273@....edu, kjlu@....edu,
        Mauro Carvalho Chehab <mchehab@...nel.org>,
        linux-media@...r.kernel.org,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] media: sti: Fix reference count leaks

On Thu, 17 Sept 2020 at 13:45, Hans Verkuil <hverkuil@...all.nl> wrote:
>
> Hi Jean-Christophe,
>
> I'll take this patch, but while reviewing it I noticed something else:
>
> On 14/06/2020 05:31, wu000273@....edu wrote:
> > From: Qiushi Wu <wu000273@....edu>
> >
> > pm_runtime_get_sync() increments the runtime PM usage counter even
> > when it returns an error code, causing incorrect ref count if
> > pm_runtime_put_noidle() is not called in error handling paths.
> > Thus call pm_runtime_put_noidle() if pm_runtime_get_sync() fails.
> >
> > Signed-off-by: Qiushi Wu <wu000273@....edu>
> > ---
> >  drivers/media/platform/sti/hva/hva-hw.c | 2 ++
> >  1 file changed, 2 insertions(+)
> >
> > diff --git a/drivers/media/platform/sti/hva/hva-hw.c b/drivers/media/platform/sti/hva/hva-hw.c
> > index 401aaafa1710..bb13348be083 100644
> > --- a/drivers/media/platform/sti/hva/hva-hw.c
> > +++ b/drivers/media/platform/sti/hva/hva-hw.c
> > @@ -272,6 +272,7 @@ static unsigned long int hva_hw_get_ip_version(struct hva_dev *hva)
> >
> >       if (pm_runtime_get_sync(dev) < 0) {
> >               dev_err(dev, "%s     failed to get pm_runtime\n", HVA_PREFIX);
> > +             pm_runtime_put_noidle(dev);
> >               mutex_unlock(&hva->protect_mutex);
>
> This appears to be a spurious mutex_unlock() since I don't see a corresponding mutex_lock.
>
> Jean-Christophe, can you check this and, if I am right, post a patch fixing this?

Probably patch should be skipped due to uncertain intentions:
https://lore.kernel.org/linux-nfs/YH+7ZydHv4+Y1hlx@kroah.com/

Best regards,
Krzysztof