linux-kernel - Re: [PATCH RFC] ftrace: Clear hashes of saved init functions

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Date:   Mon, 9 Oct 2017 11:09:42 -0400
From:   Steven Rostedt <rostedt@...dmis.org>
To:     Joel Fernandes <joelaf@...gle.com>
Cc:     linux-kernel@...r.kernel.org, Jessica Yu <jeyu@...nel.org>
Subject: Re: [PATCH RFC] ftrace: Clear hashes of saved init functions

On Sun,  8 Oct 2017 14:33:04 -0700
Joel Fernandes <joelaf@...gle.com> wrote:

>
>  static void
>  clear_mod_from_hash(struct ftrace_page *pg, struct ftrace_hash *hash)
>  {
> @@ -5771,12 +5807,24 @@ void ftrace_release_mod(struct module *mod)

This is too late. This should be done by ftrace_free_mem().

-- Steve

>  {
>  	struct ftrace_mod_map *mod_map;
>  	struct ftrace_mod_map *n;
> +	struct ftrace_mod_func *mod_func;
>  	struct dyn_ftrace *rec;
>  	struct ftrace_page **last_pg;
>  	struct ftrace_page *tmp_page = NULL;
>  	struct ftrace_page *pg;
>  	int order;
>  
> +	/* mod_map is freed via call_rcu_sched() */
> +	preempt_disable();
> +	list_for_each_entry_rcu(mod_map, &ftrace_mod_maps, list) {
> +		if (mod_map->mod != mod)
> +			continue;
> +		list_for_each_entry_rcu(mod_func, &mod_map->funcs, list) {
> +			clear_mod_func_from_hashes(mod_func);
> +		}
> +	}
> +	preempt_enable();
> +
>  	mutex_lock(&ftrace_lock);
>  
>  	if (ftrace_disabled)