linux-kernel - Re: [PATCH] init: Scream bloody murder if interrupts are enabled too early

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Message-ID: <20130308090300.GM1585@telegraafnet.nl>
Date:	Fri, 8 Mar 2013 10:03:01 +0100
From:	Ard van Breemen <ard@...egraafnet.nl>
To:	Steven Rostedt <rostedt@...dmis.org>
Cc:	LKML <linux-kernel@...r.kernel.org>,
	Andrew Morton <akpm@...ux-foundation.org>
Subject: Re: [PATCH] init: Scream bloody murder if interrupts are enabled too
 early

Hi,

On Thu, Mar 07, 2013 at 05:19:03PM -0500, Steven Rostedt wrote:
> diff --git a/init/main.c b/init/main.c
> index 63534a1..f0fe0a5 100644
> --- a/init/main.c
> +++ b/init/main.c
> @@ -539,7 +539,7 @@ asmlinkage void __init start_kernel(void)
>  	 * fragile until we cpu_idle() for the first time.
>  	 */
>  	preempt_disable();
> -	if (!irqs_disabled()) {
> +	if (WARN_ON(!irqs_disabled())) {
>  		printk(KERN_WARNING "start_kernel(): bug: interrupts were "
>  				"enabled *very* early, fixing it\n");
>  		local_irq_disable();
> 

The original code was a few versions before the WARN macros.
I think it's better to just change the printk to something like:
WARN(1,"interrupts were enabled *very* early, fixing it\n")

This will print the cause of the warning and then dump stack,
instead of having an unrelated message under the stackdump.

But: IANAM(acro)E(xpert), the real incantation might be
different.
But you are absolutely right that we should scream and shout.
This time in a way that's more in line with the others.

Regards,
Ard van Breemen.

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