On Tue, Feb 11, 2020 at 09:59:30AM +0100, Thomas Gleixner wrote:
> Uwe Kleine-König <u.kleine-koenig@xxxxxxxxxxxxxx> writes:
> > On Tue, Feb 11, 2020 at 10:35:44AM +0300, Dan Carpenter wrote:
> >> Smatch thinks that gpio_siox_irq_set_type() can be called from
> >> probe_irq_on(). In that case the call to spin_unlock_irq() would
> >> renable IRQs too early.
> >>
> >> Fixes: be8c8facc707 ("gpio: new driver to work with a 8x12 siox")
> >> Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
> >> ---
> >> drivers/gpio/gpio-siox.c | 5 +++--
> >> 1 file changed, 3 insertions(+), 2 deletions(-)
> >>
> >> diff --git a/drivers/gpio/gpio-siox.c b/drivers/gpio/gpio-siox.c
> >> index 311f66757b92..578b71760939 100644
> >> --- a/drivers/gpio/gpio-siox.c
> >> +++ b/drivers/gpio/gpio-siox.c
> >> @@ -133,10 +133,11 @@ static int gpio_siox_irq_set_type(struct irq_data *d, u32 type)
> >> struct irq_chip *ic = irq_data_get_irq_chip(d);
> >> struct gpio_siox_ddata *ddata =
> >> container_of(ic, struct gpio_siox_ddata, ichip);
> >> + unsigned long flags;
> >>
> >> - spin_lock_irq(&ddata->irqlock);
> >> + spin_lock_irqsave(&ddata->irqlock, flags);
> >> ddata->irq_type[d->hwirq] = type;
> >> - spin_unlock_irq(&ddata->irqlock);
> >> + spin_unlock_irqrestore(&ddata->irqlock, flags);
> >
> > "Normally" the .irq_set_type() callback is called from irq_set_irq_type.
> > There desc->lock is taken with raw_spin_lock_irqsave (as part of
> > irq_get_desc_buslock()), so I assume irqs are always disabled when the
> > type changes? tglx?
> >
> > If so, the better fix would be to change to spin_lock/spin_unlock
> > instead. Also given that a raw spinlock is taken, the irqlock here
> > should be changed to a raw one, too?
>
> Indeed. Looking at the driver, all of the spin_lock_irq() usage in the
> irqchip callbacks is broken.
>
> So this needs two changes:
>
> 1) Convert to raw spin lock, as this won't work on RT otherwise
>
> 2) s/lock_irq/lock/ for all irqchip callbacks.
Are you sure about the calls in gpio_siox_get_data()? This is only
called by siox_poll() which doesn't disable irqs.
Best regards
Uwe
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Pengutronix e.K. | Uwe Kleine-König |
Industrial Linux Solutions | https://www.pengutronix.de/ |
