Re: [debug patch] printk: Add a printk killswitch to robustify NMIwatchdog messages

[Arne Jansen]

On 06.06.2011 19:11, Ingo Molnar wrote:
> * Peter Zijlstra<peterz@xxxxxxxxxxxxx>  wrote:

> > +void printk_tick(void)
> > +{
> > +	if (!__this_cpu_read(printk_pending))
> > +		return;
> > +
> > +	/*
> > +	 * Try to acquire and then immediately release the
> > +	 * console semaphore. The release will do all the
> > +	 * actual magic (print out buffers, wake up klogd,
> > +	 * etc).
> > +	 */
> > +	if (console_trylock_for_printk(smp_processor_id())) {
> > +		console_unlock();
> > +		__this_cpu_write(printk_pending, 0);
> > +	}
> > +}
>
> Arne does this fix the hang you are seeing?

What do you want me to test? just replace printk_tick with the
above version? If I do that, the machine doesn't even boot up
any more.

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