x86: e820 memmap - add checking for NULL early param

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

diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c
index 292ebc7..66fd5bd 100644 (file)
--- a/arch/x86/kernel/e820.c
+++ b/arch/x86/kernel/e820.c
@@ -1198,6 +1198,9 @@ static int __init parse_memmap_opt(char *p)
        char *oldp;
        u64 start_at, mem_size;
 
+       if (!p)
+               return -EINVAL;
+
        if (!strcmp(p, "exactmap")) {
 #ifdef CONFIG_CRASH_DUMP
                /*