linux-kernel - Re: [PATCH] media: davinci: vpif_capture: fix memory leak in vpif

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Date:   Tue, 4 Jun 2019 15:15:33 +0800
From:   Yang Xiao <92siuyang@...il.com>
To:     Hans Verkuil <hverkuil@...all.nl>
Cc:     prabhakar.csengg@...il.com, mchehab@...nel.org,
        linux-media@...r.kernel.org, LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] media: davinci: vpif_capture: fix memory leak in vpif_probe()

Yes, you are correct. I will fix the issue and resubmit the patch again.

On Mon, Jun 3, 2019 at 7:55 PM Hans Verkuil <hverkuil@...all.nl> wrote:
>
> On 5/29/19 3:09 PM, Young Xiao wrote:
> > If vpif_probe() fails on vpif_probe_complete(), then memory
> > allocated at initialize_vpif() for global vpif_obj.dev[i]
> > become unreleased.
> >
> > The patch adds deallocation of vpif_obj.dev[i] on the error path.
> >
> > Signed-off-by: Young Xiao <92siuyang@...il.com>
> > ---
> >  drivers/media/platform/davinci/vpif_capture.c | 16 ++++++++++++++--
> >  1 file changed, 14 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/media/platform/davinci/vpif_capture.c b/drivers/media/platform/davinci/vpif_capture.c
> > index b5aacb0..63e6ec4 100644
> > --- a/drivers/media/platform/davinci/vpif_capture.c
> > +++ b/drivers/media/platform/davinci/vpif_capture.c
> > @@ -1621,6 +1621,14 @@ vpif_capture_get_pdata(struct platform_device *pdev)
> >       return NULL;
> >  }
> >
> > +static void free_vpif_objs(void)
> > +{
> > +     int i;
> > +
> > +     for (i = 0; i < VPIF_DISPLAY_MAX_DEVICES; i++)
> > +             kfree(vpif_obj.dev[i]);
> > +}
> > +
> >  /**
> >   * vpif_probe : This function probes the vpif capture driver
> >   * @pdev: platform device pointer
> > @@ -1701,7 +1709,10 @@ static __init int vpif_probe(struct platform_device *pdev)
> >                                 "registered sub device %s\n",
> >                                  subdevdata->name);
> >               }
> > -             vpif_probe_complete();
> > +             err = vpif_probe_complete();
> > +             if (err) {
> > +                     goto probe_subdev_out;
> > +             }
>
> No need for { and } as per kernel coding style.
>
> >       } else {
> >               vpif_obj.notifier.ops = &vpif_async_ops;
> >               err = v4l2_async_notifier_register(&vpif_obj.v4l2_dev,
> > @@ -1722,6 +1733,7 @@ static __init int vpif_probe(struct platform_device *pdev)
> >       v4l2_device_unregister(&vpif_obj.v4l2_dev);
> >  cleanup:
> >       v4l2_async_notifier_cleanup(&vpif_obj.notifier);
> > +     free_vpif_objs();
>
> This would break the case where initialize_vpif() returns an error, since
> initialize_vpif already frees these objects on error.
>
> In this case the easiest way of doing this is to just return if initialize_vpif
> returns an error. No need to clean up anything.
>
> Regards,
>
>         Hans
>
> >
> >       return err;
> >  }
> > @@ -1748,8 +1760,8 @@ static int vpif_remove(struct platform_device *device)
> >               ch = vpif_obj.dev[i];
> >               /* Unregister video device */
> >               video_unregister_device(&ch->video_dev);
> > -             kfree(vpif_obj.dev[i]);
> >       }
> > +     free_vpif_objs()
> >       return 0;
> >  }
> >
> >
>