linux-kernel - Re: [PATCH v3 02/10] livepatch: Apply vmlinux-specific KLP relocations early

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Date:   Tue, 28 Apr 2020 11:20:13 +0200 (CEST)
From:   Miroslav Benes <mbenes@...e.cz>
To:     Josh Poimboeuf <jpoimboe@...hat.com>
cc:     live-patching@...r.kernel.org, linux-kernel@...r.kernel.org,
        Peter Zijlstra <peterz@...radead.org>,
        Jessica Yu <jeyu@...nel.org>,
        Joe Lawrence <joe.lawrence@...hat.com>
Subject: Re: [PATCH v3 02/10] livepatch: Apply vmlinux-specific KLP relocations
 early

> @@ -738,18 +765,23 @@ static int klp_init_object_loaded(struct klp_patch *patch,
>  	int ret;
>  
>  	mutex_lock(&text_mutex);
> -
>  	module_disable_ro(patch->mod);
> -	ret = klp_write_object_relocations(patch->mod, obj);
> -	if (ret) {
> -		module_enable_ro(patch->mod, true);
> -		mutex_unlock(&text_mutex);
> -		return ret;
> +
> +	if (klp_is_module(obj)) {
> +		/*
> +		 * Only write module-specific relocations here
> +		 * (.klp.rela.{module}.*).  vmlinux-specific relocations were
> +		 * written earlier during the initialization of the klp module
> +		 * itself.
> +		 */
> +		ret = klp_apply_object_relocs(patch, obj);
> +		if (ret)

+                       module_enable_ro(patch->mod, true);
+                       mutex_unlock(&text_mutex);

is missing here, I think. Probably lost during rebase. It is fine after 
the next patch.

> +			return ret;
>  	}
>  
>  	arch_klp_init_object_loaded(patch, obj);
> -	module_enable_ro(patch->mod, true);
>  
> +	module_enable_ro(patch->mod, true);
>  	mutex_unlock(&text_mutex);

Miroslav