[PATCH 02/11] fbdev: Transfer video= option strings to caller; clarify ownership

[Javier Martinez Canillas]

Thomas Zimmermann <tzimmermann at suse.de> writes:

> In fb_get_options(), always duplicate the returned option string and
> transfer ownership of the memory to the function's caller.
>
> Until now, only the global option string got duplicated and transferred
> to the caller; the per-driver options were owned by fb_get_options().
> In the end, it was impossible for the function's caller to detect if
> it had to release the string's memory buffer. Hence, all calling drivers
> leak the memory buffer. The leaks have existed ever since, but drivers
> only call fb_get_option() once as part of module initialization. So the
> amount of leaked memory is not significant.
>
> Fix the semantics of fb_get_option() by unconditionally transferring
> ownership of the memory buffer to the caller. Later patches can resolve
> the memory leaks in the fbdev drivers.
>
> Signed-off-by: Thomas Zimmermann <tzimmermann at suse.de>
> ---

[...]

> +	if (option) {
> +		if (options)
> +			*option = kstrdup(options, GFP_KERNEL);
> +		else
> +			*option = NULL;
> +	}
>

I know the old code wasn't checking if kstrdup() succeeded, but you should
do it here and let the caller know. And same if (!options). So I guess the
following check can be added (to be consistent with the rest of the code):

	if (!*option)
		retval = 1;

>  	return retval;
>  }
> -- 
> 2.39.1

Best regards,
Javier