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From:   "Lad, Prabhakar" <prabhakar.csengg@gmail.com>
Date:   Tue, 4 Jun 2019 09:15:25 +0100
Message-ID: <CA+V-a8sBe53iZASaT+uJH0kMvJKNJOHYJLbTfEF+9FOVz3H=Rg@mail.gmail.com>
Subject: Re: [PATCH] media: davinci: vpif_capture: fix memory leak in vpif_probe()
To:     Young Xiao <92siuyang@gmail.com>
Cc:     Mauro Carvalho Chehab <mchehab@kernel.org>,
        linux-media <linux-media@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Hans Verkuil <hverkuil@xs4all.nl>
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Sender: linux-kernel-owner@vger.kernel.org
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Hi Young,

Thanks for the patch.

On Tue, Jun 4, 2019 at 8:49 AM Young Xiao <92siuyang@gmail.com> wrote:
>
> If vpif_probe() fails on v4l2_device_register() and 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@gmail.com>
> ---
>  drivers/media/platform/davinci/vpif_capture.c | 19 ++++++++++++++++---
>  1 file changed, 16 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/media/platform/davinci/vpif_capture.c b/drivers/media/platform/davinci/vpif_capture.c
> index b5aacb0..277d500 100644
> --- a/drivers/media/platform/davinci/vpif_capture.c
> +++ b/drivers/media/platform/davinci/vpif_capture.c
> @@ -1385,6 +1385,14 @@ static int initialize_vpif(void)
>         return err;
>  }
>
> +static void free_vpif_objs(void)
> +{
function could be made inline.

> +       int i;
> +
> +       for (i = 0; i < VPIF_DISPLAY_MAX_DEVICES; i++)

VPIF_DISPLAY_MAX_DEVICES ? this should be  VPIF_CAPTURE_MAX_DEVICES

> +               kfree(vpif_obj.dev[i]);
> +}
> +
>  static int vpif_async_bound(struct v4l2_async_notifier *notifier,
>                             struct v4l2_subdev *subdev,
>                             struct v4l2_async_subdev *asd)
> @@ -1654,7 +1662,7 @@ static __init int vpif_probe(struct platform_device *pdev)
>         err = v4l2_device_register(vpif_dev, &vpif_obj.v4l2_dev);
>         if (err) {
>                 v4l2_err(vpif_dev->driver, "Error registering v4l2 device\n");
> -               goto cleanup;
> +               goto vpif_free;
>         }
>
>         while ((res = platform_get_resource(pdev, IORESOURCE_IRQ, res_idx))) {
> @@ -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,
> @@ -1720,6 +1731,8 @@ static __init int vpif_probe(struct platform_device *pdev)
>         kfree(vpif_obj.sd);
>  vpif_unregister:
>         v4l2_device_unregister(&vpif_obj.v4l2_dev);
> +vpif_free:
> +       free_vpif_objs();
>  cleanup:
>         v4l2_async_notifier_cleanup(&vpif_obj.notifier);
>
> @@ -1748,8 +1761,8 @@ 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();

no need for this change, leave it as it is.

Cheers,
Prabhakar Lad