From f9497d51259faf7f6ecfed393a2a75879926b77a Mon Sep 17 00:00:00 2001
From: Alexey Dobriyan <adobriyan@gmail.com>
Date: Sat, 19 Aug 2017 12:57:51 +0300
Subject: genirq/ipi: Fixup checks against nr_cpu_ids

commit 8fbbe2d7cc478d1544f41f2271787c993c23a4f6 upstream.

Valid CPU ids are [0, nr_cpu_ids-1] inclusive.

Fixes: 3b8e29a82dd1 ("genirq: Implement ipi_send_mask/single()")
Fixes: f9bce791ae2a ("genirq: Add a new function to get IPI reverse mapping")
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20170819095751.GB27864@avx2
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/kernel/irq/ipi.c b/kernel/irq/ipi.c
index 1a9abc1..259a22a 100644
--- a/kernel/irq/ipi.c
+++ b/kernel/irq/ipi.c
@@ -165,7 +165,7 @@ irq_hw_number_t ipi_get_hwirq(unsigned int irq, unsigned int cpu)
 	struct irq_data *data = irq_get_irq_data(irq);
 	struct cpumask *ipimask = data ? irq_data_get_affinity_mask(data) : NULL;
 
-	if (!data || !ipimask || cpu > nr_cpu_ids)
+	if (!data || !ipimask || cpu >= nr_cpu_ids)
 		return INVALID_HWIRQ;
 
 	if (!cpumask_test_cpu(cpu, ipimask))
@@ -195,7 +195,7 @@ static int ipi_send_verify(struct irq_chip *chip, struct irq_data *data,
 	if (!chip->ipi_send_single && !chip->ipi_send_mask)
 		return -EINVAL;
 
-	if (cpu > nr_cpu_ids)
+	if (cpu >= nr_cpu_ids)
 		return -EINVAL;
 
 	if (dest) {
-- 
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