Re: [PATCH] Whine about suspicious return values from module's ->init() hook

[Andrew Morton <akpm@linux-foundation.org>]

On Mon, 4 Feb 2008 18:42:15 +0300
Alexey Dobriyan <adobriyan@sw.ru> wrote:

> One head-scratching session could be noticeably shorter with this patch...
> 

Sorry, this is not an adequate description of why you think this patch
should be merged.

> ---
> 
>  kernel/module.c |    6 ++++++
>  1 file changed, 6 insertions(+)
> 
> --- a/kernel/module.c
> +++ b/kernel/module.c
> @@ -2171,6 +2171,12 @@ sys_init_module(void __user *umod,
>  		wake_up(&module_wq);
>  		return ret;
>  	}
> +	if (ret > 0) {
> +		printk(KERN_WARNING "%s: '%s'->init suspiciously returned %d\n"
> +		       KERN_WARNING "%s: loading module anyway...\n",
> +		       __func__, mod->name, ret,
> +		       __func__);
> +	}
>  
>  	/* Now it's a first class citizen! */
>  	mutex_lock(&module_mutex);

So we add a debug statement to detect a module init function which returns
positive non-zero values, which module init functions are not supposed to
do.

Fair enough.  But a) the printk could state that more clearly and b) there
should be a comment in the code so that a developer (at whom this patch is
targetted) can go in and find out exactly what he did wrong.