__sched_setscheduler: don't do any policy checks when not "user"

The "user" parameter to __sched_setscheduler indicates whether the
change is being done on behalf of a user process or not.  If not, we
shouldn't apply any permissions checks, so don't call
security_task_setscheduler().

Signed-off-by: Jeremy Fitzhardinge <jeremy@goop.org>
Tested-by: Steve Wise <swise@opengridcomputing.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 12 insertions, 10 deletions

diff --git a/kernel/sched.c b/kernel/sched.c
index 21f7da94662e..04160d277e7a 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -5004,19 +5004,21 @@ recheck:
                         return -EPERM;
         }
 
+        if (user) {
 #ifdef CONFIG_RT_GROUP_SCHED
-        /*
-         * Do not allow realtime tasks into groups that have no runtime
-         * assigned.
-         */
-        if (user
-            && rt_policy(policy) && task_group(p)->rt_bandwidth.rt_runtime == 0)
-                return -EPERM;
+                /*
+                 * Do not allow realtime tasks into groups that have no runtime
+                 * assigned.
+                 */
+                if (rt_policy(policy) && task_group(p)->rt_bandwidth.rt_runtime == 0)
+                        return -EPERM;
 #endif
 
-        retval = security_task_setscheduler(p, policy, param);
-        if (retval)
-                return retval;
+                retval = security_task_setscheduler(p, policy, param);
+                if (retval)
+                        return retval;
+        }
+
         /*
          * make sure no PI-waiters arrive (or leave) while we are
          * changing the priority of the task: