Commit 652ffc21 authored by Greg KH's avatar Greg KH Committed by Peter Zijlstra
Browse files

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



Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/2023061204-decal-flyable-6090@gregkh
parent 5d2d4a9f

kernel/events/core.c

+28 −12
Original line number Diff line number Diff line
@@ -11408,9 +11408,32 @@ 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 = {
@@ -11447,18 +11470,11 @@ 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;

	}



out:

	return ret;