linux-kernel - Re: [PATCH] media: hi846: Fix memleak in hi846_init

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Message-ID: <4dcd261e56cf54eb409b6851128b63c5f7a2efcf.camel@posteo.de>
Date:   Sun, 26 Mar 2023 08:50:49 +0000
From:   Martin Kepplinger <martink@...teo.de>
To:     Wei Chen <harperchen1110@...il.com>
Cc:     mchehab@...nel.org, linux-media@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] media: hi846: Fix memleak in hi846_init_controls()

Am Freitag, dem 24.03.2023 um 17:24 +0000 schrieb Wei Chen:
> hi846_init_controls doesn't clean the allocated ctrl_hdlr
> in case there is a failure, which causes memleak. Add
> v4l2_ctrl_handler_free to free the resource properly.
> 
> Signed-off-by: Wei Chen <harperchen1110@...il.com>
> ---
>  drivers/media/i2c/hi846.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/media/i2c/hi846.c b/drivers/media/i2c/hi846.c
> index 7c61873b7198..c45a6511d2c1 100644
> --- a/drivers/media/i2c/hi846.c
> +++ b/drivers/media/i2c/hi846.c
> @@ -1472,6 +1472,7 @@ static int hi846_init_controls(struct hi846
> *hi846)
>         if (ctrl_hdlr->error) {
>                 dev_err(&client->dev, "v4l ctrl handler error: %d\n",
>                         ctrl_hdlr->error);
> +               v4l2_ctrl_handler_free(ctrl_hdlr);
>                 return ctrl_hdlr->error;
>         }
>  

hi Wei, thanks for the patch. It looks like I forgot that indeed, but
to me it looks like the subsequent error paths of
v4l2_fwnode_device_parse() and v4l2_ctrl_new_fwnode_properties() would
leak the same thing.

And since we only assign it to the subdev's ctrl_handler in the success
case later, you could simply add an error label:


@@ -1663,21 +1663,26 @@ static int hi846_init_controls(struct hi846
*hi846)
        if (ctrl_hdlr->error) {
                dev_err(&client->dev, "v4l ctrl handler error: %d\n",
                        ctrl_hdlr->error);
-               return ctrl_hdlr->error;
+               ret = ctrl_hdlr->error;
+               goto error;
        }
 
        ret = v4l2_fwnode_device_parse(&client->dev, &props);
        if (ret)
-               return ret;
+               goto error;
 
        ret = v4l2_ctrl_new_fwnode_properties(ctrl_hdlr,
&hi846_ctrl_ops,
                                              &props);
        if (ret)
-               return ret;
+               goto error;
 
        hi846->sd.ctrl_handler = ctrl_hdlr;
 
        return 0;
+
+error:
+       v4l2_ctrl_handler_free(ctrl_hdlr);
+       return ret;
 }
 

what do you think? thanks!

                              martin