On Wed, 29 Jul 2015, Peter Hurley wrote: > On 07/29/2015 07:53 AM, Thomas Gleixner wrote: > > On Wed, 29 Jul 2015, Peter Hurley wrote: > >> On 07/29/2015 06:32 AM, Thomas Gleixner wrote: > >>> On Wed, 29 Jul 2015, Taichi Kageyama wrote: > >>>> - Keep interrupt disabled on the CPU which is used to detect > >>>> an interrupt during the timeout of autoconfig_irq(). > >>>> + Kick printk() on the CPU which detects interrupt > >>>> from a console serial port. > >>> > >>> This is wrong to begin with. How is that supposed to work on an UP > >>> machine? Not at all. > >>> > >>> So no, fix the code which has interrupts disabled accross autoprobing > >>> and do not try to apply bandaids somewhere else. > >> > >> Like printk() from some unrelated driver? > > > > If that's the cause for the wreckage then yes, we need a way to tell > > the printk code not to call into the driver until that initialization > > step is done. It's that simple. > > Like this?
Looks about right. > --- >% -- > Subject: [PATCH] genirq: Disable printk() during irq probe > > printk() disables interrupts for extended periods of time while > outputting to console drivers. This breaks irq probing since the > triggered irq may not be serviced (in time) if scheduled on the > printk() cpu. > > Claim the console_lock() which effectively disables console output. > > Signed-off-by: Peter Hurley <[email protected]> > --- > kernel/irq/autoprobe.c | 9 +++++++++ > 1 file changed, 9 insertions(+) > > diff --git a/kernel/irq/autoprobe.c b/kernel/irq/autoprobe.c > index 0119b9d..47535d2 100644 > --- a/kernel/irq/autoprobe.c > +++ b/kernel/irq/autoprobe.c > @@ -39,6 +39,13 @@ unsigned long probe_irq_on(void) > */ > async_synchronize_full(); > mutex_lock(&probing_active); > + > + /* > + * printk() breaks irq probing - disable printk output until probe > + * completes > + */ > + console_lock(); > + > /* > * something may have generated an irq long ago and we want to > * flush such a longstanding irq before considering it as spurious. > @@ -132,6 +139,7 @@ unsigned int probe_irq_mask(unsigned long val) > } > raw_spin_unlock_irq(&desc->lock); > } > + console_unlock(); > mutex_unlock(&probing_active); > > return mask & val; > @@ -174,6 +182,7 @@ int probe_irq_off(unsigned long val) > } > raw_spin_unlock_irq(&desc->lock); > } > + console_unlock(); > mutex_unlock(&probing_active); > > if (nr_of_irqs > 1) > -- > 2.5.0 > > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
