x86: io delay - 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/io_delay.c b/arch/x86/kernel/io_delay.c
index 5921e5f0a640..1c3a66a67f83 100644
--- a/arch/x86/kernel/io_delay.c
+++ b/arch/x86/kernel/io_delay.c
@@ -103,6 +103,9 @@ void __init io_delay_init(void)
 
 static int __init io_delay_param(char *s)
 {
+        if (!s)
+                return -EINVAL;
+
         if (!strcmp(s, "0x80"))
                 io_delay_type = CONFIG_IO_DELAY_TYPE_0X80;
         else if (!strcmp(s, "0xed"))