Avoid trying to add a newly online CPU to the effective affinity mask of an
started up interrupt. That interrupt will either stay on the already online
CPU or move around for no value.

Signed-off-by: Thomas Gleixner <t...@linutronix.de>
---
 kernel/irq/cpuhotplug.c |   12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

--- a/kernel/irq/cpuhotplug.c
+++ b/kernel/irq/cpuhotplug.c
@@ -148,9 +148,17 @@ static void irq_restore_affinity_of_irq(
            !irq_data_get_irq_chip(data) || !cpumask_test_cpu(cpu, affinity))
                return;
 
-       if (irqd_is_managed_and_shutdown(data))
+       if (irqd_is_managed_and_shutdown(data)) {
                irq_startup(desc, IRQ_RESEND, IRQ_START_COND);
-       else
+               return;
+       }
+
+       /*
+        * If the interrupt can only be directed to a single target
+        * CPU then it is already assigned to a CPU in the affinity
+        * mask. No point in trying to move it around.
+        */
+       if (!irqd_is_single_target(data))
                irq_set_affinity_locked(data, affinity, false);
 }
 


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