sched/deadline: Restrict user params max value to 2^63 ns

[platform/adaptation/renesas_rcar/renesas_kernel.git] / kernel / sched / core.c

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 9fd076a..823c9d7 100644 (file)
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -3242,17 +3242,40 @@ __getparam_dl(struct task_struct *p, struct sched_attr *attr)
  * We ask for the deadline not being zero, and greater or equal
  * than the runtime, as well as the period of being zero or
  * greater than deadline. Furthermore, we have to be sure that
- * user parameters are above the internal resolution (1us); we
- * check sched_runtime only since it is always the smaller one.
+ * user parameters are above the internal resolution of 1us (we
+ * check sched_runtime only since it is always the smaller one) and
+ * below 2^63 ns (we have to check both sched_deadline and
+ * sched_period, as the latter can be zero).
  */
 static bool
 __checkparam_dl(const struct sched_attr *attr)
 {
-       return attr && attr->sched_deadline != 0 &&
-               (attr->sched_period == 0 ||
-               (s64)(attr->sched_period   - attr->sched_deadline) >= 0) &&
-               (s64)(attr->sched_deadline - attr->sched_runtime ) >= 0  &&
-               attr->sched_runtime >= (2 << (DL_SCALE - 1));
+       /* deadline != 0 */
+       if (attr->sched_deadline == 0)
+               return false;
+
+       /*
+        * Since we truncate DL_SCALE bits, make sure we're at least
+        * that big.
+        */
+       if (attr->sched_runtime < (1ULL << DL_SCALE))
+               return false;
+
+       /*
+        * Since we use the MSB for wrap-around and sign issues, make
+        * sure it's not set (mind that period can be equal to zero).
+        */
+       if (attr->sched_deadline & (1ULL << 63) ||
+           attr->sched_period & (1ULL << 63))
+               return false;
+
+       /* runtime <= deadline <= period (if period != 0) */
+       if ((attr->sched_period != 0 &&
+            attr->sched_period < attr->sched_deadline) ||
+           attr->sched_deadline < attr->sched_runtime)
+               return false;
+
+       return true;
 }
 
 /*