Hi,
On Tue, Apr 27, 2021 at 07:47:41PM -0300, Luis Claudio R. Goncalves wrote:
> On Tue, Apr 27, 2021 at 06:10:09PM -0400, Joe Korty wrote:
> > Balance local_irq_{disable,enable} usage in irq_forced_thread_fn
> >
> > Re: 0152-genirq-Allow-disabling-of-softirq-processing-in-irq-.patch
> >
> > In 4.9.263-rt177, irq_forced_thread_fn has potentially unbalanced calls to
> > local_irq_disable ... local_irq_enable. This is probably not intentional.
> >
> > I am not absolutely sure what the proper fix is. Attached is an example
> > of what that might look like.
> >
> > [ Issue detected via compiler warning, using a sufficiently advanced gcc ]
> >
> > Signed-off-by: Joe Korty <joe.korty@xxxxxxxxxxxxxxxxx>
>
> Joe, I fell a bit behind on v4.9-rt and intend to get up to date this
> weekend. I am now satisfied with my current backport of the futex changes
> from v4.9.264 and my 96h of pi_stress testing.
>
> Your patch makes sense, taking v4.19-rt as reference, but I will wait
> for comments from the wise people you listed on the Cc: before taking
> action.
I had to resolve the same merge conflict in v4.4-rt. The fix from Joe
resolve to the same solution I've done in v4.4-rt
>
> Best regards,
> Luis
>
> >
> > Index: b/kernel/irq/manage.c
> > ===================================================================
> > --- a/kernel/irq/manage.c
> > +++ b/kernel/irq/manage.c
> > @@ -1035,6 +1035,9 @@ irq_forced_thread_fn(struct irq_desc *de
> > atomic_inc(&desc->threads_handled);
> >
> > irq_finalize_oneshot(desc, action);
> > +
Nit there is no new line here in upstream, dd652c6ab49b ("genirq:
Disable interrupts for force threaded handlers")
> > + if (!IS_ENABLED(CONFIG_PREEMPT_RT_BASE))
> > + local_irq_enable();
> > /*
> > * Interrupts which have real time requirements can be set up
> > * to avoid softirq processing in the thread handler. This is
> > @@ -1043,8 +1046,6 @@ irq_forced_thread_fn(struct irq_desc *de
> > if (irq_settings_no_softirq_call(desc))
> > _local_bh_enable();
> > else
> > - if (!IS_ENABLED(CONFIG_PREEMPT_RT_BASE))
> > - local_irq_enable();
> > local_bh_enable();
> > return ret;
> > }
> ---end quoted text---
Thanks,
Daniel
