Subject: Re: [PATCH 1/7] drivers/macintosh/via-pmu-led.c: Add of_node_put to avoid memory leak

From: walter harms <[email-masked]>
Date: Tue, 31 Aug 2010 17:49:19 +0200

Julia Lawall schrieb:
> Add a call to of_node_put in the error handling code following a call to
> of_find_node_by_path.
> 
> The semantic match that finds this problem is as follows:
> (http://coccinelle.lip6.fr/)
> 
> // <smpl>
> @r exists@
> local idexpression x;
> expression E,E1;
> statement S;
> @@
> 
> *x = 
> (of_find_node_by_path
> |of_find_node_by_name
> |of_find_node_by_phandle
> |of_get_parent
> |of_get_next_parent
> |of_get_next_child
> |of_find_compatible_node
> |of_match_node
> )(...);
> ...
> if (x == NULL) S
> <... when != x = E
> *if (...) {
>   ... when != of_node_put(x)
>       when != if (...) { ... of_node_put(x); ... }
> (
>   return <+...x...+>;
> |
> *  return ...;
> )
> }
> ...>
> of_node_put(x);
> // </smpl>
> 
> Signed-off-by: Julia Lawall <[email-masked]>
> 
> ---
>  drivers/macintosh/via-pmu-led.c |    4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/macintosh/via-pmu-led.c b/drivers/macintosh/via-pmu-led.c
> index d242976..19c3718 100644
> --- a/drivers/macintosh/via-pmu-led.c
> +++ b/drivers/macintosh/via-pmu-led.c
> @@ -92,8 +92,10 @@ static int __init via_pmu_led_init(void)
>  	if (dt == NULL)
>  		return -ENODEV;
>  	model = of_get_property(dt, "model", NULL);
> -	if (model == NULL)
> +	if (model == NULL) {
> +		of_node_put(dt);
>  		return -ENODEV;
> +	}
>  	if (strncmp(model, "PowerBook", strlen("PowerBook")) != 0 &&
>  	    strncmp(model, "iBook", strlen("iBook")) != 0 &&
>  	    strcmp(model, "PowerMac7,2") != 0 &&
> 

is there any rule that says when to use strncmp ? it seems perfecly valid to use strcpy here
(what is done in the last cmp).

re,
 wh