genirq: Annotate irq stats data races

Both the per cpu stats and the accumulated count are accessed lockless and
can be concurrently modified. That's intentional and the stats are a rough
estimate anyway. Annotate them with data_race().

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20201210194043.067097663@linutronix.de

diff --git a/kernel/irq/irqdesc.c b/kernel/irq/irqdesc.c
index 20a54fa..02b446a 100644 (file)
--- a/kernel/irq/irqdesc.c
+++ b/kernel/irq/irqdesc.c
@@ -943,10 +943,10 @@ unsigned int kstat_irqs(unsigned int irq)
        if (!irq_settings_is_per_cpu_devid(desc) &&
            !irq_settings_is_per_cpu(desc) &&
            !irq_is_nmi(desc))
-           return desc->tot_count;
+               return data_race(desc->tot_count);
 
        for_each_possible_cpu(cpu)
-               sum += *per_cpu_ptr(desc->kstat_irqs, cpu);
+               sum += data_race(*per_cpu_ptr(desc->kstat_irqs, cpu));
        return sum;
 }
 

diff --git a/kernel/irq/proc.c b/kernel/irq/proc.c
index 72513ed..9813878 100644 (file)
--- a/kernel/irq/proc.c
+++ b/kernel/irq/proc.c
@@ -488,9 +488,10 @@ int show_interrupts(struct seq_file *p, void *v)
        if (!desc || irq_settings_is_hidden(desc))
                goto outsparse;
 
-       if (desc->kstat_irqs)
+       if (desc->kstat_irqs) {
                for_each_online_cpu(j)
-                       any_count |= *per_cpu_ptr(desc->kstat_irqs, j);
+                       any_count |= data_race(*per_cpu_ptr(desc->kstat_irqs, j));
+       }
 
        if ((!desc->action || irq_desc_is_chained(desc)) && !any_count)
                goto outsparse;