[patch 05/30] genirq: Annotate irq stats data races
From: Thomas Gleixner <hidden>
Date: 2020-12-10 19:51:49
Also in:
dri-devel, intel-gfx, linux-gpio, linux-pci, linux-rdma, linux-s390, lkml, xen-devel
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 <redacted> --- kernel/irq/irqdesc.c | 4 ++-- kernel/irq/proc.c | 5 +++-- 2 files changed, 5 insertions(+), 4 deletions(-)
--- 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; } --- a/kernel/irq/proc.c +++ b/kernel/irq/proc.c
@@ -488,9 +488,10 @@ int show_interrupts(struct seq_file *p, 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;