X-Git-Url: http://drtracing.org/?a=blobdiff_plain;f=kernel%2Fsched.c;h=2a43a581ead32c2ae0396c8f13e3b484a89003c8;hb=60aa605dfce2976e54fa76e805ab0f221372d4d9;hp=54d67b94f1a9f159e7f9ea07f9ab0e2bc626c569;hpb=6e29ec5701e9d44fa02b96c1c5c45f7516182b65;p=deliverable%2Flinux.git

diff --git a/kernel/sched.c b/kernel/sched.c
index 54d67b94f1a9..2a43a581ead3 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -9917,6 +9917,13 @@ static int sched_rt_global_constraints(void)
 	if (sysctl_sched_rt_period <= 0)
 		return -EINVAL;
 
+	/*
+	 * There's always some RT tasks in the root group
+	 * -- migration, kstopmachine etc..
+	 */
+	if (sysctl_sched_rt_runtime == 0)
+		return -EBUSY;
+
 	spin_lock_irqsave(&def_rt_bandwidth.rt_runtime_lock, flags);
 	for_each_possible_cpu(i) {
 		struct rt_rq *rt_rq = &cpu_rq(i)->rt;