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From:   Austin Kim <austindh.kim@gmail.com>
Date:   Thu, 5 Sep 2019 07:39:53 +0900
Message-ID: <CADLLry5WHSTyWzRa0bg0Dsnm8rO-cVF=i1CkzKN+DMXv9wq-Xw@mail.gmail.com>
Subject: Re: [PATCH] media: meson: Add NULL check after the call to kmalloc()
To:     Greg KH <gregkh@linuxfoundation.org>
Cc:     mchehab@kernel.org, khilman@baylibre.com, mjourdan@baylibre.com,
        devel@driverdev.osuosl.org, linux-kernel@vger.kernel.org,
        linux-amlogic@lists.infradead.org,
        linux-arm-kernel@lists.infradead.org, linux-media@vger.kernel.org
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2019=EB=85=84 9=EC=9B=94 4=EC=9D=BC (=EC=88=98) =EC=98=A4=ED=9B=84 5:45, Gr=
eg KH <gregkh@linuxfoundation.org>=EB=8B=98=EC=9D=B4 =EC=9E=91=EC=84=B1:
>
> On Wed, Sep 04, 2019 at 05:22:32PM +0900, Austin Kim wrote:
> > If the kmalloc() return NULL, the NULL pointer dereference will occur.
> >       new_ts->ts =3D ts;
> >
> > Add exception check after the call to kmalloc() is made.
> >
> > Signed-off-by: Austin Kim <austindh.kim@gmail.com>
> > ---
> >  drivers/staging/media/meson/vdec/vdec_helpers.c | 4 ++++
> >  1 file changed, 4 insertions(+)
> >
> > diff --git a/drivers/staging/media/meson/vdec/vdec_helpers.c b/drivers/=
staging/media/meson/vdec/vdec_helpers.c
> > index f16948b..e7e56d5 100644
> > --- a/drivers/staging/media/meson/vdec/vdec_helpers.c
> > +++ b/drivers/staging/media/meson/vdec/vdec_helpers.c
> > @@ -206,6 +206,10 @@ void amvdec_add_ts_reorder(struct amvdec_session *=
sess, u64 ts, u32 offset)
> >       unsigned long flags;
> >
> >       new_ts =3D kmalloc(sizeof(*new_ts), GFP_KERNEL);
> > +     if (!new_ts) {
> > +             dev_err(sess->core->dev, "Failed to kmalloc()\n");
>
> Did you run this through checkpatch?  I think it will say that this line
> is not ok.
>
> > +             return;
>
> Shouldn't you return an -ENOMEM error somehow?

I agreed with your feedback.
Let me take a look at the code more and then resend the patch if necessary.

Thanks,
Austin Kim
>
> thanks,
>
> greg k-h