1 files changed, 11 insertions, 3 deletions

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 03a67f09404c..a4869bd426ca 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -7675,6 +7675,17 @@ static int tg_set_rt_bandwidth(struct task_group *tg,
 {
         int i, err = 0;
 
+        /*
+         * Disallowing the root group RT runtime is BAD, it would disallow the
+         * kernel creating (and or operating) RT threads.
+         */
+        if (tg == &root_task_group && rt_runtime == 0)
+                return -EINVAL;
+
+        /* No period doesn't make any sense. */
+        if (rt_period == 0)
+                return -EINVAL;
+
         mutex_lock(&rt_constraints_mutex);
         read_lock(&tasklist_lock);
         err = __rt_schedulable(tg, rt_period, rt_runtime);
@@ -7731,9 +7742,6 @@ static int sched_group_set_rt_period(struct task_group *tg, long rt_period_us)
         rt_period = (u64)rt_period_us * NSEC_PER_USEC;
         rt_runtime = tg->rt_bandwidth.rt_runtime;
 
-        if (rt_period == 0)
-                return -EINVAL;
-
         return tg_set_rt_bandwidth(tg, rt_period, rt_runtime);
 }