Re: [patch] kobject: don't oops on null kobject.name

[Andrew Morton <akpm@osdl.org>]

Chuck Ebbert <76306.1226@compuserve.com> wrote:
>
> kobject_get_path() will oops if one of the component names is
> NULL.  Fix that by returning NULL instead of oopsing.
> 
> Signed-off-by: Chuck Ebbert <76306.1226@compuserve.com>
> ---
> 
> Helge, this fixes your "2.6.15 OOPS while trying to mount cdrom".
> 
> Probably not the best fix, but It Works For Me (TM).
> 
> --- 2.6.15a.orig/lib/kobject.c
> +++ 2.6.15a/lib/kobject.c
> @@ -72,6 +72,8 @@ static int get_kobj_path_length(struct k
>  	 * Add 1 to strlen for leading '/' of each level.
>  	 */
>  	do {
> +		if (kobject_name(parent) == NULL)
> +			return 0;
>  		length += strlen(kobject_name(parent)) + 1;
>  		parent = parent->parent;
>  	} while (parent);
> @@ -107,6 +109,8 @@ char *kobject_get_path(struct kobject *k
>  	int len;
>  
>  	len = get_kobj_path_length(kobj);
> +	if (len == 0)
> +		return NULL;
>  	path = kmalloc(len, gfp_mask);
>  	if (!path)
>  		return NULL;

I'd have thought that we'd want the test right at the start of
kobject_add() - fail it if ->name is zero.  I don't know if that'd work for
all callers, but kobject_add() does play around with the ->name field and
will go oops if ->name==NULL and debugging is enabled.

Why did you choose kobject_get_path()?