PFAIR: don't crash on weight 1.0 tasks

Avoid division by zero.

1 files changed, 11 insertions, 1 deletions

diff --git a/litmus/sched_pfair.c b/litmus/sched_pfair.c
index beb303c352..ad082a3a6f 100755
--- a/litmus/sched_pfair.c
+++ b/litmus/sched_pfair.c
@@ -684,7 +684,8 @@ static void init_subtask(struct subtask* sub, unsigned long i,
         if (2 * quanta >= period) {
                 /* heavy */
                 tmp = (sub->deadline - (i + 1)) * period;
-                if (do_div(tmp, (period - quanta))) /* ceil */
+                if (period > quanta &&
+                    do_div(tmp, (period - quanta))) /* ceil */
                         tmp++;
                 sub->group_deadline = (quanta_t) tmp;
         } else
@@ -734,6 +735,15 @@ static long pfair_admit_task(struct task_struct* t)
                 return -EINVAL;
         }
 
+        if (quanta == period) {
+                /* special case: task has weight 1.0 */
+                printk(KERN_INFO
+                       "Admitting weight 1.0 task. (%s/%d, %llu, %llu).\n",
+                       t->comm, t->pid, quanta, period);
+                quanta = 1;
+                period = 1;
+        }
+
         param = kmalloc(sizeof(struct pfair_param) +
                         quanta * sizeof(struct subtask), GFP_ATOMIC);