Hello Thomas,
On Thu, Aug 06, 2020 at 10:33:06PM +0200, Thomas Gleixner wrote:
> Uwe Kleine-König <u.kleine-koenig@xxxxxxxxxxxxxx> writes:
> > On Thu, Aug 06, 2020 at 08:50:45PM +0200, Thomas Gleixner wrote:
> >> handle_nested_irq() does not care. It cares about thread context,
> >> external reentrancy protection for the same nested interrupt and that
> >> the nested interrupt has a thread handler.
> >>
> >> The latter is what goes belly up because w/o that threaded bit set the
> >> GPIO core fails to set nested thread. So if a consumer requests an
> >> interrupt with request_any_context_irq() then that fails to select
> >> thread mode which means the threaded handler is not set causing
> >> handle_nested_irq() to fail.
> >
> > For a caller of request_threaded_irq() that passes a relevant hardirq
> > handler the hardirq handler is never called but request_threaded_irq()
> > doesn't fail. The handler is just replaced by irq_nested_primary_handler
> > in __setup_irq(). Is that a bug? (I didn't test, just read the code, so I
> > might have missed something.)
>
> Depends on what the threaded handler expects what the primary handler
> has done. It might just work or not :)
So we need something like:
diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index 48c38e09c673..31777a0b79df 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -1393,12 +1393,18 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
ret = -EINVAL;
goto out_mput;
}
- /*
- * Replace the primary handler which was provided from
- * the driver for non nested interrupt handling by the
- * dummy function which warns when called.
- */
- new->handler = irq_nested_primary_handler;
+
+ if (new->handler == NULL) {
+ /* Scream loud if the primary handler gets called */
+ new->handler = irq_nested_primary_handler;
+ } else {
+ /*
+ * The handler won't be called as the requestor expects,
+ * so refuse to install the handler
+ */
+ ret = -EINVAL;
+ goto out_mput;
+ }
} else {
if (irq_settings_can_thread(desc)) {
ret = irq_setup_forced_threading(new);
? Do we need to care for other allowed values of new->handler? Maybe
irq_default_primary_handler?
> > Is this bad enough to justify sending this patch to stable?
>
> Yes, a Cc: stable and a Fixes: tag is justified.
That would be
Fixes: be8c8facc707 ("gpio: new driver to work with a 8x12 siox")
Best regards
Uwe
--
Pengutronix e.K. | Uwe Kleine-König |
Industrial Linux Solutions | https://www.pengutronix.de/ |
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