Problem: CONFIG_KALLSYMS is not set + kernel/module.c

[linux@arm.linux.org.uk (Russell King - ARM Linux)]

This is not ARM specific, please post it more widely.  Also consider
sending it to the person responsible for the module code as listed in
MAINTAINERS.  Thanks.

On Sun, Jul 29, 2012 at 08:27:17AM -0700, Mark Hinds wrote:
>
> In linux-3.2.xx I've been getting kernel dumps when I modprobe some
> modules with CONFIG_KALLSYMS diabled - nls_base.ko for example.
> I traced the problem to kernel/module.c, line 2607 or there about.
>
> Starting with:
> ptr = module_alloc_update_bounds(mod->init_size);
>
> If mod->init_size == 0 then foobar happens. I assume that there is
> no init section in some modules when CONFIG_KALLSYMS is disabled.
>
> Here is my fix:
>
> Index: kernel/module.c
> ===================================================================
> --- kernel/module.c	(.../linux-3.2.24/kernel/module.c)	(revision 9084)
> +++ kernel/module.c	(.../linux-3.2.24-ces/kernel/module.c)	(working copy)
> @@ -2604,20 +2604,24 @@
>  	memset(ptr, 0, mod->core_size);
>  	mod->module_core = ptr;
>
> -	ptr = module_alloc_update_bounds(mod->init_size);
> -	/*
> -	 * The pointer to this block is stored in the module structure
> -	 * which is inside the block. This block doesn't need to be
> -	 * scanned as it contains data and code that will be freed
> -	 * after the module is initialized.
> -	 */
> -	kmemleak_ignore(ptr);
> -	if (!ptr && mod->init_size) {
> -		module_free(mod, mod->module_core);
> -		return -ENOMEM;
> +#warning ### CES/zoro fix problem with mod->init_size == 0
> +	if (mod->init_size) {
> +		ptr = module_alloc_update_bounds(mod->init_size);
> +		/*
> +	 	* The pointer to this block is stored in the module structure
> +	 	* which is inside the block. This block doesn't need to be
> +	 	* scanned as it contains data and code that will be freed
> +	 	* after the module is initialized.
> +	 	*/
> +		kmemleak_ignore(ptr);
> +		if (!ptr) {
> +			module_free(mod, mod->module_core);
> +			return -ENOMEM;
> +		}
> +		memset(ptr, 0, mod->init_size);
> +		mod->module_init = ptr;
>  	}
> -	memset(ptr, 0, mod->init_size);
> -	mod->module_init = ptr;
> +	else mod->module_init = NULL;
>
>  	/* Transfer each section which specifies SHF_ALLOC */
>  	DEBUGP("final section addresses:\n");
>
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