From c61935fd0e7f087a643827b4bf5ef646963c10fa Mon Sep 17 00:00:00 2001
From: Ingo Molnar <mingo@elte.hu>
Date: Tue, 22 Jan 2008 11:24:58 +0100
Subject: [PATCH] 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 <mingo@elte.hu>
---
kernel/sched.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/kernel/sched.c b/kernel/sched.c
index 37cf07aa41647..e76b11ca6df32 100644
--- 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;
--
2.30.2