From ae0839f165a565cc2288676173a5568fe91bda98 Mon Sep 17 00:00:00 2001 From: Sultan Alsawaf Date: Sat, 25 May 2019 22:48:20 -0700 Subject: [PATCH] kernel: Don't allow IRQ affinity masks to have more than one CPU Even with an affinity mask that has multiple CPUs set, IRQs always run on the first CPU in their affinity mask. Drivers that register an IRQ affinity notifier (such as pm_qos) will therefore have an incorrect assumption of where an IRQ is affined. Fix the IRQ affinity mask deception by forcing it to only contain one set CPU. Signed-off-by: Sultan Alsawaf --- kernel/irq/manage.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c index 9cbe640df..0506e53f6 100755 --- a/kernel/irq/manage.c +++ b/kernel/irq/manage.c @@ -267,6 +267,8 @@ int irq_do_set_affinity(struct irq_data *data, const struct cpumask *mask, else prog_mask = &tmp_mask; } else { + /* IRQs only run on the first CPU in the affinity mask */ + mask = cpumask_of(cpumask_first(mask)); prog_mask = mask; }