linux-kernel - Re: [RFC PATCH v2 2/2] module: When modifying a module's text ignore modules which are going away too

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Message-ID: <20161027094934.296d668d@gandalf.local.home>
Date:   Thu, 27 Oct 2016 09:49:34 -0400
From:   Steven Rostedt <rostedt@...dmis.org>
To:     Aaron Tomlin <atomlin@...hat.com>
Cc:     linux-kernel@...r.kernel.org, rusty@...tcorp.com.au,
        Jessica Yu <jeyu@...hat.com>
Subject: Re: [RFC PATCH v2 2/2] module: When modifying a module's text
 ignore modules which are going away too


This looks line to me. Rusty, do you have any issues with this?

Maybe we should add a comment to why a going module shouldn't be
converted to ro (because of ftrace and kprobes). But other than that,
I have no issue with it.

I also added Jessica to the Cc as I notice she will be the new module
maintainer: http://lwn.net/Articles/704653/

-- Steve


On Thu, 27 Oct 2016 10:36:06 +0100
Aaron Tomlin <atomlin@...hat.com> wrote:

> By default, during the access permission modification of a module's core
> and init pages, we only ignore modules that are malformed. Albeit for a
> module which is going away, it does not make sense to change its text to
> RO since the module should be RW, before deallocation.
> 
> This patch makes set_all_modules_text_ro() skip modules which are going
> away too.
> 
> Signed-off-by: Aaron Tomlin <atomlin@...hat.com>
> ---
>  kernel/module.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/kernel/module.c b/kernel/module.c
> index ff93ab8..2a383df 100644
> --- a/kernel/module.c
> +++ b/kernel/module.c
> @@ -1969,7 +1969,8 @@ void set_all_modules_text_ro(void)
>  
>  	mutex_lock(&module_mutex);
>  	list_for_each_entry_rcu(mod, &modules, list) {
> -		if (mod->state == MODULE_STATE_UNFORMED)
> +		if (mod->state == MODULE_STATE_UNFORMED ||
> +			mod->state == MODULE_STATE_GOING)
>  			continue;
>  
>  		frob_text(&mod->core_layout, set_memory_ro);