diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 74f5b58..e36ae4b 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -2501,11 +2501,11 @@
 	bool first = 1;
 	size_t left = *lenp;
 	unsigned long bitmap_len = table->maxlen;
-	unsigned long *bitmap = (unsigned long *) table->data;
+	unsigned long *bitmap = *(unsigned long **) table->data;
 	unsigned long *tmp_bitmap = NULL;
 	char tr_a[] = { '-', ',', '\n' }, tr_b[] = { ',', '\n', 0 }, c;
 
-	if (!bitmap_len || !left || (*ppos && !write)) {
+	if (!bitmap || !bitmap_len || !left || (*ppos && !write)) {
 		*lenp = 0;
 		return 0;
 	}