linux-kernel - Re: [RFC PATCH 1/2] module: Ensure a module's state is set accordingly during module coming cleanup code

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Message-ID: <87funk3p6f.fsf@rustcorp.com.au>
Date:   Wed, 26 Oct 2016 11:24:32 +1030
From:   Rusty Russell <rusty@...tcorp.com.au>
To:     Aaron Tomlin <atomlin@...hat.com>, linux-kernel@...r.kernel.org
Cc:     rostedt@...dmis.org, "Jessica Yu" <jeyu@...hat.com>
Subject: Re: [RFC PATCH 1/2] module: Ensure a module's state is set accordingly during module coming cleanup code

Aaron Tomlin <atomlin@...hat.com> writes:
> In load_module() in the event of an error, for e.g. unknown module
> parameter(s) specified we go to perform some module coming clean up
> operations. At this point the module is still in a "formed" state
> when it is actually going away.
>
> This patch updates the module's state accordingly to ensure anyone on the
> module_notify_list waiting for a module going away notification will be
> notified accordingly.

I recall a similar proposal before.

I've audited all the subscribers to check they didn't look at
mod->state; they seem OK.

We actually do this in the init-failed path, so this should be OK.

Acked-by: Rusty Russell <rusty@...tcorp.com.au>

Thanks,
Rusty.

> Signed-off-by: Aaron Tomlin <atomlin@...hat.com>
> ---
>  kernel/module.c | 1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/kernel/module.c b/kernel/module.c
> index f57dd63..ff93ab8 100644
> --- a/kernel/module.c
> +++ b/kernel/module.c
> @@ -3708,6 +3708,7 @@ static int load_module(struct load_info *info, const char __user *uargs,
>   sysfs_cleanup:
>  	mod_sysfs_teardown(mod);
>   coming_cleanup:
> +	mod->state = MODULE_STATE_GOING;
>  	blocking_notifier_call_chain(&module_notify_list,
>  				     MODULE_STATE_GOING, mod);
>  	klp_module_going(mod);
> -- 
> 2.5.5