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authorThomas Gleixner <tglx@linutronix.de>2020-03-06 16:03:46 +0300
committerThomas Gleixner <tglx@linutronix.de>2020-03-08 13:06:41 +0300
commitda90921acc62c71d27729ae211ccfda5370bf75b (patch)
treefb26cfaf7dd63e0092d50824c2b2b8af93056b53 /kernel/irq
parent1f85b1f5e1f5541272abedc19ba7b6c5b564c228 (diff)
downloadlinux-da90921acc62c71d27729ae211ccfda5370bf75b.tar.xz
genirq: Sanitize state handling in check_irq_resend()
The code sets IRQS_REPLAY unconditionally whether the resend happens or not. That doesn't have bad side effects right now, but inconsistent state is always a latent source of problems. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Marc Zyngier <maz@kernel.org> Link: https://lkml.kernel.org/r/20200306130623.882129117@linutronix.de
Diffstat (limited to 'kernel/irq')
-rw-r--r--kernel/irq/resend.c22
1 files changed, 14 insertions, 8 deletions
diff --git a/kernel/irq/resend.c b/kernel/irq/resend.c
index a21fc4eeedc7..bef72dcfb79b 100644
--- a/kernel/irq/resend.c
+++ b/kernel/irq/resend.c
@@ -93,6 +93,8 @@ static int irq_sw_resend(struct irq_desc *desc)
*/
int check_irq_resend(struct irq_desc *desc)
{
+ int err = 0;
+
/*
* We do not resend level type interrupts. Level type interrupts
* are resent by hardware when they are still active. Clear the
@@ -106,13 +108,17 @@ int check_irq_resend(struct irq_desc *desc)
if (desc->istate & IRQS_REPLAY)
return -EBUSY;
- if (desc->istate & IRQS_PENDING) {
- desc->istate &= ~IRQS_PENDING;
- desc->istate |= IRQS_REPLAY;
+ if (!(desc->istate & IRQS_PENDING))
+ return 0;
- if (!desc->irq_data.chip->irq_retrigger ||
- !desc->irq_data.chip->irq_retrigger(&desc->irq_data))
- return irq_sw_resend(desc);
- }
- return 0;
+ desc->istate &= ~IRQS_PENDING;
+
+ if (!desc->irq_data.chip->irq_retrigger ||
+ !desc->irq_data.chip->irq_retrigger(&desc->irq_data))
+ err = irq_sw_resend(desc);
+
+ /* If the retrigger was successfull, mark it with the REPLAY bit */
+ if (!err)
+ desc->istate |= IRQS_REPLAY;
+ return err;
}