linux-kernel - Re: [PATCH] lktdm: Bring support for hardlockup, softlockup and hung task crashes

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Date:	Sun, 16 May 2010 13:36:36 +0400
From:	Cyrill Gorcunov <gorcunov@...il.com>
To:	Frederic Weisbecker <fweisbec@...il.com>
Cc:	Andrew Morton <akpm@...ux-foundation.org>,
	LKML <linux-kernel@...r.kernel.org>,
	Simon Kagstrom <simon.kagstrom@...insight.net>,
	Ingo Molnar <mingo@...e.hu>, Don Zickus <dzickus@...hat.com>
Subject: Re: [PATCH] lktdm: Bring support for hardlockup, softlockup and
	hung task crashes

On Sun, May 16, 2010 at 07:39:51AM +0200, Frederic Weisbecker wrote:
...  
>  static struct jprobe lkdtm;
> @@ -320,6 +326,20 @@ static void lkdtm_do_action(enum ctype which)
>  		memset(data, 0x78, len);
>  		break;
>  	}
> +	case SOFTLOCKUP:
> +		preempt_disable();
> +		for (;;)
> +			cpu_relax();
> +		break;
> +	case HARDLOCKUP:
> +		local_irq_disable();
> +		for (;;)
> +			cpu_relax();
> +		break;
> +	case HUNG_TASK:
> +		set_current_state(TASK_UNINTERRUPTIBLE);
> +		schedule();
> +		break;
>  	case NONE:
>  	default:
>  		break;

Looks good to me. Btw perhaps we may simplify it a bit:

	case HARDLOCKUP:
		local_irq_disable();
	case SOFTLOCKUP:
		preempt_disable();
		for (;;)
			cpu_relax();
		break;

since it'll save a few bytes. What do you think? Did I miss
something?

	-- Cyrill
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