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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>
This commit is contained in:
Marc Zyngier 2020-10-05 15:02:17 +01:00 committed by Linus Walleij
parent 47e538d86d
commit 8b81edd80b
1 changed files with 15 additions and 2 deletions
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17
drivers/gpio/gpio-pca953x.c
View File

@ -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);
}