Commit 8b81edd8 authored Oct 05, 2020 by Marc Zyngier Committed by Linus Walleij Oct 07, 2020

gpio: pca953x: Survive spurious interrupts



The pca953x driver never checks the result of irq_find_mapping(),
which returns 0 when no mapping is found. When a spurious interrupt
is delivered (which can happen under obscure circumstances), the
kernel explodes as it still tries to handle the error code as
a real interrupt.

Handle this particular case and warn on spurious interrupts.

Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20201005140217.1390851-1-maz@kernel.org


Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

parent 47e538d8

drivers/gpio/gpio-pca953x.c

+15 −2

Original line number	Diff line number	Diff line
		@@ -824,8 +824,21 @@ static irqreturn_t pca953x_irq_handler(int irq, void *devid)
		ret = pca953x_irq_pending(chip, pending);
		mutex_unlock(&chip->i2c_lock);

		for_each_set_bit(level, pending, gc->ngpio)
		handle_nested_irq(irq_find_mapping(gc->irq.domain, level));
		if (ret) {
		ret = 0;

		for_each_set_bit(level, pending, gc->ngpio) {
		int nested_irq = irq_find_mapping(gc->irq.domain, level);

		if (unlikely(nested_irq <= 0)) {
		dev_warn_ratelimited(gc->parent, "unmapped interrupt %d\n", level);
		continue;
		}

		handle_nested_irq(nested_irq);
		ret = 1;
		}
		}

		return IRQ_RETVAL(ret);
		}

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