Re: [PATCH] irq: Guard handle_bad_irq log messages

[Guenter Roeck]

On 12/02/2017 08:52 AM, Joe Perches wrote:
> On Sat, 2017-12-02 at 08:29 -0800, Guenter Roeck wrote:
> > An interrupt storm on a bad interrupt will cause the kernel
> > log to be clogged.
> >
> > [   60.089234] ->handle_irq():  ffffffffbe2f803f,
> > [   60.090455] 0xffffffffbf2af380
> > [   60.090510] handle_bad_irq+0x0/0x2e5
> > [   60.090522] ->irq_data.chip(): ffffffffbf2af380,
> > [   60.090553]    IRQ_NOPROBE set
> > [   60.090584] ->handle_irq():  ffffffffbe2f803f,
> > [   60.090590] handle_bad_irq+0x0/0x2e5
> > [   60.090596] ->irq_data.chip(): ffffffffbf2af380,
> > [   60.090602] 0xffffffffbf2af380
> > [   60.090608] ->action():           (null)
> > [   60.090779] handle_bad_irq+0x0/0x2e5
> >
> > This was seen when running an upstream kernel on Acer Chromebook R11.
> > The system was unstable as result.
> >
> > Guard the log message with __printk_ratelimit to reduce the impact.
> > This won't prevent the interrupt storm from happening, but at least
> > the system remains stable.
>
> Thanks.
>
> There is also dummychip.c
>
> Perhaps this should be updated in the
> static inline in kernel/irq/debug.h instead.

Agreed, makes sense. I'll send an updated patch.

Guenter

> > diff --git a/kernel/irq/handle.c b/kernel/irq/handle.c
> []
> > @@ -28,9 +28,11 @@
> >    */
> >   void handle_bad_irq(struct irq_desc *desc)
> >   {
> > +	static DEFINE_RATELIMIT_STATE(ratelimit, 5 * HZ, 5);
> >   	unsigned int irq = irq_desc_get_irq(desc);
> >   
> > -	print_irq_desc(irq, desc);
> > +	if (__ratelimit(&ratelimit))
> > +		print_irq_desc(irq, desc);
> >   	kstat_incr_irqs_this_cpu(desc);
> >   	ack_bad_irq(irq);
> >   }