Re: [PATCH 2/2] ftrace: Adjust priority of ftrace module notifier

[Steven Rostedt]

On Fri, 29 Jan 2016 01:43:47 -0500
Jessica Yu <jeyu@xxxxxxxxxx> wrote:


> ---
>  kernel/trace/ftrace.c | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
> 
> diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
> index eca592f..bdd7bfc 100644
> --- a/kernel/trace/ftrace.c
> +++ b/kernel/trace/ftrace.c
> @@ -5067,7 +5067,12 @@ static int ftrace_module_notify(struct notifier_block *self,
>  
>  struct notifier_block ftrace_module_nb = {
>  	.notifier_call = ftrace_module_notify,
> -	.priority = INT_MIN,	/* Run after anything that can remove kprobes */
> +	/*
> +	 * Run after anything that can remove kprobes and
> +	 * after livepatch's going notifier, but run before
> +	 * livepatch's coming notifier.
> +	 */
> +	.priority = INT_MIN+1,
>  };
>  
>  void __init ftrace_init(void)

Actually, I rather break up the ftrace notifiers into two different
notifiers. One for coming and one for going (I use to have that before
hard coding the module updates in the module code).

Have the coming notifier be INT_MAX, where it runs before everything
else (which it should, as tracing should be enabled then). And have the
module going to stay INT_MIN to run after everything.

-- Steve