perf/core: Fix installing cgroup event into cpu

index 4df5b69..fb5b167 100644
@@ -933,31 +933,41 @@ list_update_cgroup_event(struct perf_event *event,
 {
 	struct perf_cpu_context *cpuctx;
 	struct list_head *cpuctx_entry;
+	struct perf_cgroup *cgrp;
 
 	if (!is_cgroup_event(event))
 		return;
 
-	if (add && ctx->nr_cgroups++)
-		return;
-	else if (!add && --ctx->nr_cgroups)
-		return;
 	/*
 	 * Because cgroup events are always per-cpu events,
 	 * this will always be called from the right CPU.
 	 */
 	cpuctx = __get_cpu_context(ctx);
-	cpuctx_entry = &cpuctx->cgrp_cpuctx_entry;
-	/* cpuctx->cgrp is NULL unless a cgroup event is active in this CPU .*/
-	if (add) {
-		struct perf_cgroup *cgrp = perf_cgroup_from_task(current, ctx);
+	cgrp = perf_cgroup_from_task(current, ctx);
 
-		list_add(cpuctx_entry, this_cpu_ptr(&cgrp_cpuctx_list));
-		if (cgroup_is_descendant(cgrp->css.cgroup, event->cgrp->css.cgroup))
+	/*
+	 * if only the cgroup is running on this cpu,
+	 * we put/remove this cgroup into cpu context.
+	 * Or it would case mismatch in following cgroup
+	 * events at event_filter_match()
+	 */
+	if (cgroup_is_descendant(cgrp->css.cgroup, event->cgrp->css.cgroup)) {
+		if (add)
 			cpuctx->cgrp = cgrp;
-	} else {
-		list_del(cpuctx_entry);
-		cpuctx->cgrp = NULL;
+		else
+			cpuctx->cgrp = NULL;
 	}
+
+	if (add && ctx->nr_cgroups++)
+		return;
+	else if (!add && --ctx->nr_cgroups)
+		return;
+
+	cpuctx_entry = &cpuctx->cgrp_cpuctx_entry;
+	if (add)
+		list_add(cpuctx_entry, this_cpu_ptr(&cgrp_cpuctx_list));
+	else
+		list_del(cpuctx_entry);
 }
 
 #else /* !CONFIG_CGROUP_PERF */

@@ -2284,6 +2294,7 @@ static int  __perf_install_in_context(void *info)
 	struct perf_event_context *ctx = event->ctx;
 	struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
 	struct perf_event_context *task_ctx = cpuctx->task_ctx;
+	struct perf_cgroup *cgrp;
 	bool reprogram = true;
 	int ret = 0;
 

@@ -2311,6 +2322,18 @@ static int  __perf_install_in_context(void *info)
 		raw_spin_lock(&task_ctx->lock);
 	}
 
+	if (is_cgroup_event(event)) {
+		/*
+		 * Only care about cgroup events.
+		 *
+		 * If only the task belongs to cgroup of this event,
+		 * we will continue the installment
+		 */
+		cgrp = perf_cgroup_from_task(current, ctx);
+		reprogram = cgroup_is_descendant(cgrp->css.cgroup,
+					event->cgrp->css.cgroup);
+	}
+
 	if (reprogram) {
 		ctx_sched_out(ctx, cpuctx, EVENT_TIME);
 		add_event_to_ctx(event, ctx);