Re: [PATCH v3 4/7] gpio: gpiolib: fix allocation order in hierarchical IRQ domains

[Oleksij Rempel]

Hi Tommaso,

On Fri, Mar 13, 2026 at 11:42:34AM +0100, Tommaso Merciai wrote:
> Hi Oleksij,
> Thanks for your patch.
> 
> I'm working on DSI support for RZ/G3E
> 
> from this morning rebasing on top of next-20260312 I'm seeing
> the following:
> I found out the the issue is related to the interrupt of the adv7535
> bridge:
> 
>         adv7535: hdmi1@3d {
>                 compatible = "adi,adv7535";
>                 ...
>                 ...
>                 interrupts-extended = <&pinctrl RZG3E_GPIO(L, 4) IRQ_TYPE_EDGE_FALLING>;
> 
> RZ/G3E is using:
>  - drivers/pinctrl/renesas/pinctrl-rzg2l.c
> 
> Reverting this patch fix the issue.
> (git revert a23463beb3d5)

Thank you for the feedback! If I understand the problem correctly, the
adv7535 is asserting its IRQ line early during probe, which creates an
irq storm due to a missing handler.

My patch moved irq_domain_set_info() after the parent allocation. When
the parent allocates the IRQ, the pending hardware interrupt fires
immediately. Because the child descriptor isn't fully configured yet, it
routes to handle_bad_irq. This fails to acknowledge the hardware
interrupt, locking up the CPU and causing the RCU stall.

I hope splitting the irq_domain_set_info() should fix the regression.
Can you please test if this change resolve the RCU stalls on your setup:

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 13dd97344b26..376daeddbbbb 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -1628,6 +1628,9 @@ static int gpiochip_hierarchy_irq_domain_alloc(struct irq_domain *d,
 	}
 	gpiochip_dbg(gc, "found parent hwirq %u\n", parent_hwirq);
 
+	irq_set_handler(irq, girq->handler);
+	irq_set_handler_data(irq, gc);
+
 	/* This parent only handles asserted level IRQs */
 	ret = girq->populate_parent_alloc_arg(gc, &gpio_parent_fwspec,
 					      parent_hwirq, parent_type);
@@ -1655,13 +1658,7 @@ static int gpiochip_hierarchy_irq_domain_alloc(struct irq_domain *d,
 	 * We set handle_bad_irq because the .set_type() should
 	 * always be invoked and set the right type of handler.
 	 */
-	irq_domain_set_info(d,
-			    irq,
-			    hwirq,
-			    gc->irq.chip,
-			    gc,
-			    girq->handler,
-			    NULL, NULL);
+	irq_domain_set_hwirq_and_chip(d, irq, hwirq, gc->irq.chip, gc);
 	irq_set_probe(irq);
 
 	return 0;
-- 
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