perf/core: Fix narrow startup race when creating the perf nr_addr_filters sysfs file

[ Upstream commit 652ffc2104ec1f69dd4a46313888c33527145ccf ]

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/2023061204-decal-flyable-6090@gregkh
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/kernel/events/core.c b/kernel/events/core.c
index 58ecb1c..f22c540 100644 (file)
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -11413,9 +11413,32 @@ static DEVICE_ATTR_RW(perf_event_mux_interval_ms);
 static struct attribute *pmu_dev_attrs[] = {
        &dev_attr_type.attr,
        &dev_attr_perf_event_mux_interval_ms.attr,
+       &dev_attr_nr_addr_filters.attr,
+       NULL,
+};
+
+static umode_t pmu_dev_is_visible(struct kobject *kobj, struct attribute *a, int n)
+{
+       struct device *dev = kobj_to_dev(kobj);
+       struct pmu *pmu = dev_get_drvdata(dev);
+
+       if (!pmu->nr_addr_filters)
+               return 0;
+
+       return a->mode;
+
+       return 0;
+}
+
+static struct attribute_group pmu_dev_attr_group = {
+       .is_visible = pmu_dev_is_visible,
+       .attrs = pmu_dev_attrs,
+};
+
+static const struct attribute_group *pmu_dev_groups[] = {
+       &pmu_dev_attr_group,
        NULL,
 };
-ATTRIBUTE_GROUPS(pmu_dev);
 
 static int pmu_bus_running;
 static struct bus_type pmu_bus = {
@@ -11452,18 +11475,11 @@ static int pmu_dev_alloc(struct pmu *pmu)
        if (ret)
                goto free_dev;
 
-       /* For PMUs with address filters, throw in an extra attribute: */
-       if (pmu->nr_addr_filters)
-               ret = device_create_file(pmu->dev, &dev_attr_nr_addr_filters);
-
-       if (ret)
-               goto del_dev;
-
-       if (pmu->attr_update)
+       if (pmu->attr_update) {
                ret = sysfs_update_groups(&pmu->dev->kobj, pmu->attr_update);
-
-       if (ret)
-               goto del_dev;
+               if (ret)
+                       goto del_dev;
+       }
 
 out:
        return ret;