This is a note to let you know that I've just added the patch titled
irqchip/apple-aic: Fix irq_disable from within irq handlers
to the 5.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
irqchip-apple-aic-fix-irq_disable-from-within-irq-ha.patch
and it can be found in the queue-5.14 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 90cc658bf065df89aa0867dc3fcc624fd570d96c
Author: Sven Peter <sven@xxxxxxxxxxxxx>
Date: Thu Aug 12 12:09:42 2021 +0200
irqchip/apple-aic: Fix irq_disable from within irq handlers
[ Upstream commit 60a1cd10b222e004f860d14651e80089c77e8e6b ]
When disable_irq_nosync for an interrupt is called from within its
interrupt handler, this interrupt is only marked as disabled with the
intention to mask it when it triggers again.
The AIC hardware however automatically masks the interrupt when it is read.
aic_irq_eoi then unmasks it again if it's not disabled *and* not masked.
This results in a state mismatch between the hardware state and the
state kept in irq_data: The hardware interrupt is masked but
IRQD_IRQ_MASKED is not set. Any further calls to unmask_irq will directly
return and the interrupt can never be enabled again.
Fix this by keeping the hardware and irq_data state in sync by unmasking in
aic_irq_eoi if and only if the irq_data state also assumes the interrupt to
be unmasked.
Fixes: 76cde2639411 ("irqchip/apple-aic: Add support for the Apple Interrupt Controller")
Signed-off-by: Sven Peter <sven@xxxxxxxxxxxxx>
Acked-by: Hector Martin <marcan@xxxxxxxxx>
Signed-off-by: Marc Zyngier <maz@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20210812100942.17206-1-sven@xxxxxxxxxxxxx
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/irqchip/irq-apple-aic.c b/drivers/irqchip/irq-apple-aic.c
index b8c06bd8659e..6fc145aacaf0 100644
--- a/drivers/irqchip/irq-apple-aic.c
+++ b/drivers/irqchip/irq-apple-aic.c
@@ -226,7 +226,7 @@ static void aic_irq_eoi(struct irq_data *d)
* Reading the interrupt reason automatically acknowledges and masks
* the IRQ, so we just unmask it here if needed.
*/
- if (!irqd_irq_disabled(d) && !irqd_irq_masked(d))
+ if (!irqd_irq_masked(d))
aic_irq_unmask(d);
}
