Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
Merge tag 'perf-urgent-2025-03-07' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull perf event fixes from Ingo Molnar:
"Fix a race between PMU registration and event creation, and fix
pmus_lock vs. pmus_srcu lock ordering"
* tag 'perf-urgent-2025-03-07' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
perf/core: Fix perf_pmu_register() vs. perf_init_event()
perf/core: Fix pmus_lock vs. pmus_srcu ordering
+28
-4
+28
-4
kernel/events/core.c
+28
-4
kernel/events/core.c
···
11830
11830
static struct lock_class_key cpuctx_mutex;
11831
11831
static struct lock_class_key cpuctx_lock;
11832
11832
11833
+
static bool idr_cmpxchg(struct idr *idr, unsigned long id, void *old, void *new)
11834
+
{
11835
+
void *tmp, *val = idr_find(idr, id);
11836
+
11837
+
if (val != old)
11838
+
return false;
11839
+
11840
+
tmp = idr_replace(idr, new, id);
11841
+
if (IS_ERR(tmp))
11842
+
return false;
11843
+
11844
+
WARN_ON_ONCE(tmp != val);
11845
+
return true;
11846
+
}
11847
+
11833
11848
int perf_pmu_register(struct pmu *pmu, const char *name, int type)
11834
11849
{
11835
11850
int cpu, ret, max = PERF_TYPE_MAX;
···
11871
11856
if (type >= 0)
11872
11857
max = type;
11873
11858
11874
-
ret = idr_alloc(&pmu_idr, pmu, max, 0, GFP_KERNEL);
11859
+
ret = idr_alloc(&pmu_idr, NULL, max, 0, GFP_KERNEL);
11875
11860
if (ret < 0)
11876
11861
goto free_pdc;
11877
11862
···
11879
11864
11880
11865
type = ret;
11881
11866
pmu->type = type;
11867
+
atomic_set(&pmu->exclusive_cnt, 0);
11882
11868
11883
11869
if (pmu_bus_running && !pmu->dev) {
11884
11870
ret = pmu_dev_alloc(pmu);
···
11928
11912
if (!pmu->event_idx)
11929
11913
pmu->event_idx = perf_event_idx_default;
11930
11914
11915
+
/*
11916
+
* Now that the PMU is complete, make it visible to perf_try_init_event().
11917
+
*/
11918
+
if (!idr_cmpxchg(&pmu_idr, pmu->type, NULL, pmu))
11919
+
goto free_context;
11931
11920
list_add_rcu(&pmu->entry, &pmus);
11932
-
atomic_set(&pmu->exclusive_cnt, 0);
11921
+
11933
11922
ret = 0;
11934
11923
unlock:
11935
11924
mutex_unlock(&pmus_lock);
11936
11925
11937
11926
return ret;
11927
+
11928
+
free_context:
11929
+
free_percpu(pmu->cpu_pmu_context);
11938
11930
11939
11931
free_dev:
11940
11932
if (pmu->dev && pmu->dev != PMU_NULL_DEV) {
···
11963
11939
{
11964
11940
mutex_lock(&pmus_lock);
11965
11941
list_del_rcu(&pmu->entry);
11942
+
idr_remove(&pmu_idr, pmu->type);
11943
+
mutex_unlock(&pmus_lock);
11966
11944
11967
11945
/*
11968
11946
* We dereference the pmu list under both SRCU and regular RCU, so
···
11974
11948
synchronize_rcu();
11975
11949
11976
11950
free_percpu(pmu->pmu_disable_count);
11977
-
idr_remove(&pmu_idr, pmu->type);
11978
11951
if (pmu_bus_running && pmu->dev && pmu->dev != PMU_NULL_DEV) {
11979
11952
if (pmu->nr_addr_filters)
11980
11953
device_remove_file(pmu->dev, &dev_attr_nr_addr_filters);
···
11981
11956
put_device(pmu->dev);
11982
11957
}
11983
11958
free_pmu_context(pmu);
11984
-
mutex_unlock(&pmus_lock);
11985
11959
}
11986
11960
EXPORT_SYMBOL_GPL(perf_pmu_unregister);
11987
11961