[PATCH] tick/sched: check skew_tick kernel parameter's validity

[Sergey Shtylyov]

In skew_tick(), the result of get_option() call is ignored, so even if a
value of the skew_tick kernel parameter was not specified (or specified
as a list or range), the kernel won't complain. Add the missing check...

Found by Linux Verification Center (linuxtesting.org) with the Svace static
analysis tool.

Signed-off-by: Sergey Shtylyov <s.shtylyov@xxxxxxxxxxxx>

---
The patch is against the timers/nohz branch of the tip.git repo...

 kernel/time/tick-sched.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index c1ee0b256445..34ceccdd49b5 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -1483,7 +1483,8 @@ static int sched_skew_tick;
 
 static int __init skew_tick(char *str)
 {
-	get_option(&str, &sched_skew_tick);
+	if (get_option(&str, &sched_skew_tick) != 1)
+		return -EINVAL;
 
 	return 0;
 }
-- 
2.55.0