/* Recursion avoidance in each contexts */
int recursion[PERF_NR_CONTEXTS];
+
+ /* Keeps track of cpu being initialized/exited */
+ bool online;
};
static DEFINE_PER_CPU(struct swevent_htable, swevent_htable);
hwc->state = !(flags & PERF_EF_START);
head = find_swevent_head(swhash, event);
- if (WARN_ON_ONCE(!head))
+ if (!head) {
+ /*
+ * We can race with cpu hotplug code. Do not
+ * WARN if the cpu just got unplugged.
+ */
+ WARN_ON_ONCE(swhash->online);
return -EINVAL;
+ }
hlist_add_head_rcu(&event->hlist_entry, head);
if (attr.freq) {
if (attr.sample_freq > sysctl_perf_event_sample_rate)
return -EINVAL;
+ } else {
+ if (attr.sample_period & (1ULL << 63))
+ return -EINVAL;
}
/*
struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
mutex_lock(&swhash->hlist_mutex);
+ swhash->online = true;
if (swhash->hlist_refcount > 0) {
struct swevent_hlist *hlist;
static void __perf_event_exit_context(void *__info)
{
struct perf_event_context *ctx = __info;
- struct perf_event *event, *tmp;
+ struct perf_event *event;
perf_pmu_rotate_stop(ctx->pmu);
- list_for_each_entry_safe(event, tmp, &ctx->pinned_groups, group_entry)
- __perf_remove_from_context(event);
- list_for_each_entry_safe(event, tmp, &ctx->flexible_groups, group_entry)
+ rcu_read_lock();
+ list_for_each_entry_rcu(event, &ctx->event_list, event_entry)
__perf_remove_from_context(event);
+ rcu_read_unlock();
}
static void perf_event_exit_cpu_context(int cpu)
{
struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
+ perf_event_exit_cpu_context(cpu);
+
mutex_lock(&swhash->hlist_mutex);
+ swhash->online = false;
swevent_hlist_release(swhash);
mutex_unlock(&swhash->hlist_mutex);
-
- perf_event_exit_cpu_context(cpu);
}
#else
static inline void perf_event_exit_cpu(int cpu) { }