genirq: Sanitize state handling in check_irq_resend() (da90921a) · Commits · 戴 / test

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

kernel/irq/resend.c

+14 −8

Original line number	Diff line number	Diff line
		@@ -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) {
		if (!(desc->istate & IRQS_PENDING))
		return 0;

		desc->istate &= ~IRQS_PENDING;
		desc->istate \|= IRQS_REPLAY;

		if (!desc->irq_data.chip->irq_retrigger \|\|
		!desc->irq_data.chip->irq_retrigger(&desc->irq_data))
		return irq_sw_resend(desc);
		}
		return 0;
		err = irq_sw_resend(desc);

		/* If the retrigger was successfull, mark it with the REPLAY bit */
		if (!err)
		desc->istate \|= IRQS_REPLAY;
		return err;
		}

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