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Subject[PATCH] gpio: pca953x: Survive spurious interrupts
Date
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>
---
drivers/gpio/gpio-pca953x.c | 17 +++++++++++++++--
1 file changed, 15 insertions(+), 2 deletions(-)

diff --git a/drivers/gpio/gpio-pca953x.c b/drivers/gpio/gpio-pca953x.c
index fb61f2fc6ed7..c2d6121c48c9 100644
--- a/drivers/gpio/gpio-pca953x.c
+++ b/drivers/gpio/gpio-pca953x.c
@@ -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);
}
--
2.28.0
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