x86: idle process - add checking for NULL early param

Signed-off-by: Cyrill Gorcunov <gorcunov@gmail.com>
Cc: akpm@linux-foundation.org
Cc: andi@firstfloor.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 3 insertions, 0 deletions

diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
index ba370dc8685b..58325a6604a4 100644
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -164,6 +164,9 @@ void __cpuinit select_idle_routine(const struct cpuinfo_x86 *c)
 
 static int __init idle_setup(char *str)
 {
+        if (!str)
+                return -EINVAL;
+
         if (!strcmp(str, "poll")) {
                 printk("using polling idle threads.\n");
                 pm_idle = poll_idle;