On Mon, 1 Feb 2016, Jessica Yu wrote:
> +/* Called from the module loader during module coming/going states */
> +extern int klp_module_enable(struct module *mod);
> +extern void klp_module_disable(struct module *mod);
We do not use 'extern' keyword in header files. It is redundant.
Unfortunately, the situation differs among header files and it is hard to
be consistent.
> + /*
> + * Each module has to know that the coming handler has
> + * been called. We never know what module will get
> + * patched by a new patch.
> + */
> + mod->klp_alive = true;
This comment should fixed too.
Note: we still need klp_alive, because the race is still there even
without notifiers.
> +void klp_module_disable(struct module *mod)
> {
> - int ret;
> - struct module *mod = data;
> struct klp_patch *patch;
> struct klp_object *obj;
>
> - if (action != MODULE_STATE_COMING && action != MODULE_STATE_GOING)
> - return 0;
> + if (mod->state != MODULE_STATE_GOING)
> + return;
This is similar to what Petr proposed. We must be in MODULE_STATE_GOING
here. We could WARN here and return.
> diff --git a/kernel/module.c b/kernel/module.c
> index b05d466..71c77ed 100644
> --- a/kernel/module.c
> +++ b/kernel/module.c
> @@ -3375,6 +3378,10 @@ static int complete_formation(struct module *mod,
> struct load_info *info)
> mutex_unlock(&module_mutex);
>
> ftrace_module_enable(mod);
> + err = klp_module_enable(mod);
> + if (err)
> + goto out;
> +
if (err)
return err;
module_mutex is already unlocked so no need to jump to out.
Apart from these minor things and Petr's remarks it looks ok.
Thanks for fixing this.
Miroslav
