linux-kernel - Re: [PATCH] media: davinci: vpif_display: Mix memory leak on probe error path

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Date:   Thu, 2 Aug 2018 10:51:51 +0100
From:   "Lad, Prabhakar" <prabhakar.csengg@...il.com>
To:     Anton Vasilyev <vasilyev@...ras.ru>
Cc:     Mauro Carvalho Chehab <mchehab@...nel.org>,
        linux-media <linux-media@...r.kernel.org>,
        LKML <linux-kernel@...r.kernel.org>, ldv-project@...uxtesting.org
Subject: Re: [PATCH] media: davinci: vpif_display: Mix memory leak on probe
 error path

Hi,

thank you for the patch.

On Fri, Jul 27, 2018 at 12:52 PM, Anton Vasilyev <vasilyev@...ras.ru> wrote:
> If vpif_probe() fails on v4l2_device_register() 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 and
> removes duplicated check on platform_data presence.
>
> Found by Linux Driver Verification project (linuxtesting.org).
>
> Signed-off-by: Anton Vasilyev <vasilyev@...ras.ru>
> ---
>  drivers/media/platform/davinci/vpif_display.c | 24 ++++++++++++-------
>  1 file changed, 16 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/media/platform/davinci/vpif_display.c b/drivers/media/platform/davinci/vpif_display.c
> index 7be636237acf..0f324055cc9f 100644
> --- a/drivers/media/platform/davinci/vpif_display.c
> +++ b/drivers/media/platform/davinci/vpif_display.c
> @@ -1114,6 +1114,14 @@ static int initialize_vpif(void)
>         return err;
>  }
>
> +static void free_vpif_objs(void)
> +{
> +       int i;
> +
> +       for (i = 0; i < VPIF_DISPLAY_MAX_DEVICES; i++)
> +               kfree(vpif_obj.dev[i]);
> +}
> +
>  static int vpif_async_bound(struct v4l2_async_notifier *notifier,
>                             struct v4l2_subdev *subdev,
>                             struct v4l2_async_subdev *asd)
> @@ -1255,11 +1263,6 @@ static __init int vpif_probe(struct platform_device *pdev)
>                 return -EINVAL;
>         }
>
> -       if (!pdev->dev.platform_data) {
> -               dev_warn(&pdev->dev, "Missing platform data.  Giving up.\n");
> -               return -EINVAL;
> -       }
> -
Could make this as a separate patch.

>         vpif_dev = &pdev->dev;
>         err = initialize_vpif();
>
> @@ -1271,7 +1274,7 @@ 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");
> -               return err;
> +               goto vpif_free;
>         }
>
>         while ((res = platform_get_resource(pdev, IORESOURCE_IRQ, res_idx))) {
> @@ -1314,7 +1317,10 @@ static __init int vpif_probe(struct platform_device *pdev)
>                         if (vpif_obj.sd[i])
>                                 vpif_obj.sd[i]->grp_id = 1 << i;
>                 }
> -               vpif_probe_complete();
> +               err = vpif_probe_complete();
> +               if (err) {
> +                       goto probe_subdev_out;
> +               }

{} braces are not needed

>         } else {
>                 vpif_obj.notifier.subdevs = vpif_obj.config->asd;
>                 vpif_obj.notifier.num_subdevs = vpif_obj.config->asd_sizes[0];
> @@ -1334,6 +1340,8 @@ 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();
>
Just put the for loop here instead.

>         return err;
>  }
> @@ -1355,8 +1363,8 @@ 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();
>
Just leave this as is, as its already looping and freeing up the objects.

>         return 0;
>  }
> --
> 2.18.0
>

Cheers,
--Prabhakar Lad