[PATCH] media: airspy: fix memory leak in airspy probe

[PATCH] media: airspy: fix memory leak in airspy probe

[Dongliang Mu]

From: Dongliang Mu <mudongliangabcd@gmail.com>

The commit ca9dc8d06ab6 ("media: airspy: respect the DMA coherency
 rules") moves variable buf from stack to heap, however, it only frees
buf in the error handling code, missing deallocation in the success
path.

Fix this by freeing buf in the success path since this variable does not
have any references in other code.

Fixes: ca9dc8d06ab6 ("media: airspy: respect the DMA coherency rules")
Reported-by: syzbot+bb25f85e5aa482864dc0@syzkaller.appspotmail.com
Signed-off-by: Dongliang Mu <mudongliangabcd@gmail.com>
---
 drivers/media/usb/airspy/airspy.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/media/usb/airspy/airspy.c b/drivers/media/usb/airspy/airspy.c
index 240a7cc56777..7b1c40132555 100644
--- a/drivers/media/usb/airspy/airspy.c
+++ b/drivers/media/usb/airspy/airspy.c
@@ -1070,6 +1070,10 @@ static int airspy_probe(struct usb_interface *intf,
 				ret);
 		goto err_free_controls;
 	}
+
+	/* Free buf if success*/
+	kfree(buf);
+
 	dev_info(s->dev, "Registered as %s\n",
 			video_device_node_name(&s->vdev));
 	dev_notice(s->dev, "SDR API is still slightly experimental and functionality changes may follow\n");
-- 
2.35.1

Re: [PATCH] media: airspy: fix memory leak in airspy probe

[Tommaso Merciai]

Hi Dongliang,

On Thu, Aug 11, 2022 at 12:57:00PM +0800, Dongliang Mu wrote:
> From: Dongliang Mu <mudongliangabcd@gmail.com>
> 
> The commit ca9dc8d06ab6 ("media: airspy: respect the DMA coherency
>  rules") moves variable buf from stack to heap, however, it only frees
> buf in the error handling code, missing deallocation in the success
> path.
> 
> Fix this by freeing buf in the success path since this variable does not
> have any references in other code.
> 
> Fixes: ca9dc8d06ab6 ("media: airspy: respect the DMA coherency rules")
> Reported-by: syzbot+bb25f85e5aa482864dc0@syzkaller.appspotmail.com
> Signed-off-by: Dongliang Mu <mudongliangabcd@gmail.com>
> ---
>  drivers/media/usb/airspy/airspy.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/drivers/media/usb/airspy/airspy.c b/drivers/media/usb/airspy/airspy.c
> index 240a7cc56777..7b1c40132555 100644
> --- a/drivers/media/usb/airspy/airspy.c
> +++ b/drivers/media/usb/airspy/airspy.c
> @@ -1070,6 +1070,10 @@ static int airspy_probe(struct usb_interface *intf,
>  				ret);
>  		goto err_free_controls;
>  	}
> +
> +	/* Free buf if success*/
> +	kfree(buf);
> +

buf var is only used to print the fw version during the probe.
I think you are right we need to free this.

Reviewed-by: Tommaso Merciai <tommaso.merciai@amarulasolution.com>

>  	dev_info(s->dev, "Registered as %s\n",
>  			video_device_node_name(&s->vdev));
>  	dev_notice(s->dev, "SDR API is still slightly experimental and functionality changes may follow\n");
> -- 
> 2.35.1
> 

Regards,
Tommaso

-- 
Tommaso Merciai
Embedded Linux Engineer
tommaso.merciai@amarulasolutions.com
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