diff -Nrup a/count.c b/count.c

--- a/count.c	2014-09-17 15:18:18.000000000 -0400

+++ b/count.c	2015-07-02 21:48:48.906419324 -0400

@@ -115,6 +115,16 @@ time_cmp(void *a, void *b)

 static int

 syscall_cmp(void *a, void *b)

 {

+	const char *name_a = sysent[*((int *) a)].sys_name;

+	const char *name_b = sysent[*((int *) b)].sys_name;

+

+	if (name_a == name_b)

+		return 0;

+	if (!name_a)

+		return -1;

+	if (!name_b)

+		return 1;

+

 	return strcmp(sysent[*((int *) a)].sys_name,

 		      sysent[*((int *) b)].sys_name);

 }