genirq: Use the correct variable for note_interrupt (70433c01) · Commits · 戴 / test

note_interrupt wants to be called with the combined result of all handlers called, not with the last one. If it's a shared interrupt then the last handler might return IRQ_NONE often enough to trigger the spurious dectector which turns off a perfectly fine working interrupt line. Bug was introduced in commit (genirq: Simplify handle_irq_event()). Yes, I really messed up there. First the variable ret should not have been named differently to avoid similarity with retval. Second it should have been declared in the do {} loop. Rename it to res and move it into the do {} loop and vanish under a huge brown paperbag. Reported-bisected-tested-by:

Ingo Molnar <mingo@elte.hu> Signed-off-by:

Thomas Gleixner <tglx@linutronix.de>

kernel/irq/handle.c

+9 −7

Original line number	Diff line number	Diff line
		@@ -54,24 +54,26 @@ static void warn_no_thread(unsigned int irq, struct irqaction *action)
		irqreturn_t
		handle_irq_event_percpu(struct irq_desc desc, struct irqaction action)
		{
		irqreturn_t ret, retval = IRQ_NONE;
		irqreturn_t retval = IRQ_NONE;
		unsigned int random = 0, irq = desc->irq_data.irq;

		do {
		irqreturn_t res;

		trace_irq_handler_entry(irq, action);
		ret = action->handler(irq, action->dev_id);
		trace_irq_handler_exit(irq, action, ret);
		res = action->handler(irq, action->dev_id);
		trace_irq_handler_exit(irq, action, res);

		if (WARN_ON_ONCE(!irqs_disabled()))
		local_irq_disable();

		switch (ret) {
		switch (res) {
		case IRQ_WAKE_THREAD:
		/*
		* Set result to handled so the spurious check
		* does not trigger.
		*/
		ret = IRQ_HANDLED;
		res = IRQ_HANDLED;

		/*
		* Catch drivers which return WAKE_THREAD but
		@@ -105,7 +107,7 @@ handle_irq_event_percpu(struct irq_desc desc, struct irqaction action)
		break;
		}

		retval \|= ret;
		retval \|= res;
		action = action->next;
		} while (action);

		@@ -113,7 +115,7 @@ handle_irq_event_percpu(struct irq_desc desc, struct irqaction action)
		add_interrupt_randomness(irq);

		if (!noirqdebug)
		note_interrupt(irq, desc, ret);
		note_interrupt(irq, desc, retval);
		return retval;
		}

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