1 files changed, 27 insertions, 1 deletions

diff --git a/kernel/irq/cpuhotplug.c b/kernel/irq/cpuhotplug.c
index 638eb9c83d9f..9eb09aef0313 100644
--- a/kernel/irq/cpuhotplug.c
+++ b/kernel/irq/cpuhotplug.c
@@ -18,8 +18,34 @@
 static inline bool irq_needs_fixup(struct irq_data *d)
 {
         const struct cpumask *m = irq_data_get_effective_affinity_mask(d);
+        unsigned int cpu = smp_processor_id();
 
-        return cpumask_test_cpu(smp_processor_id(), m);
+#ifdef CONFIG_GENERIC_IRQ_EFFECTIVE_AFF_MASK
+        /*
+         * The cpumask_empty() check is a workaround for interrupt chips,
+         * which do not implement effective affinity, but the architecture has
+         * enabled the config switch. Use the general affinity mask instead.
+         */
+        if (cpumask_empty(m))
+                m = irq_data_get_affinity_mask(d);
+
+        /*
+         * Sanity check. If the mask is not empty when excluding the outgoing
+         * CPU then it must contain at least one online CPU. The outgoing CPU
+         * has been removed from the online mask already.
+         */
+        if (cpumask_any_but(m, cpu) < nr_cpu_ids &&
+            cpumask_any_and(m, cpu_online_mask) >= nr_cpu_ids) {
+                /*
+                 * If this happens then there was a missed IRQ fixup at some
+                 * point. Warn about it and enforce fixup.
+                 */
+                pr_warn("Eff. affinity %*pbl of IRQ %u contains only offline CPUs after offlining CPU %u\n",
+                        cpumask_pr_args(m), d->irq, cpu);
+                return true;
+        }
+#endif
+        return cpumask_test_cpu(cpu, m);
 }
 
 static bool migrate_one_irq(struct irq_desc *desc)