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

From: Steven Rostedt
Date: Thu Oct 27 2016 - 09:49:47 EST



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@xxxxxxxxxx> 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@xxxxxxxxxx>
> ---
> 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);