x86: smpboot maxcpus - 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, 2 insertions, 1 deletions

diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index fd933b5465b6..e47bfac70c38 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -1452,7 +1452,8 @@ static int __init parse_maxcpus(char *arg)
 {
         extern unsigned int maxcpus;
 
-        maxcpus = simple_strtoul(arg, NULL, 0);
+        if (arg)
+                maxcpus = simple_strtoul(arg, NULL, 0);
         return 0;
 }
 early_param("maxcpus", parse_maxcpus);