sched: group scheduler, set uid share fix

setting cpu share to 1 causes hangs, as reported in: http://bugzilla.kernel.org/show_bug.cgi?id=9779 as the default share is 1024, the values of 0 and 1 can indeed cause problems. Limit it to 2 or higher values. These values can only be set by the root user - but still it makes sense to protect against nonsensical values. Signed-off-by: Ingo Molnar <[email protected]>
mna · Jan 22, 2008 · c61935f · c61935f
1 parent d384e35
commit c61935f
Showing 1 changed file with 8 additions and 0 deletions.
diff --git a/kernel/sched.c b/kernel/sched.c
@@ -7153,6 +7153,14 @@ int sched_group_set_shares(struct task_group *tg, unsigned long shares)
 {
 	int i;
 
+	/*
+	 * A weight of 0 or 1 can cause arithmetics problems.
+	 * (The default weight is 1024 - so there's no practical
+	 *  limitation from this.)
+	 */
+	if (shares < 2)
+		shares = 2;
+
 	spin_lock(&tg->lock);
 	if (tg->shares == shares)
 		goto done;