Index: lib/libkvm/tests/kvm_geterr_test.c
===================================================================
--- lib/libkvm/tests/kvm_geterr_test.c
+++ lib/libkvm/tests/kvm_geterr_test.c
@@ -26,6 +26,8 @@
 #include <sys/cdefs.h>
 __FBSDID("$FreeBSD$");
 
+#include <sys/types.h>
+#include <sys/sysctl.h>
 #include <sys/param.h>
 #include <errno.h>
 #include <fcntl.h>
@@ -125,6 +127,15 @@
 	    "error message changed: %s", error_msg);
 	ATF_REQUIRE_MSG(kvm_close(kd) == 0, "kvm_close failed: %s",
 	    strerror(errno));
+
+	/* sanity check of value read from kvm_read */
+	int sysctl_maxcpus;
+	size_t len = sizeof(sysctl_maxcpus);
+        retcode = sysctlbyname("kern.smp.maxcpus", &sysctl_maxcpus, &len, NULL, 0);
+	ATF_REQUIRE_MSG(retcode == 0, "sysctl read failed : %d", retcode);
+	ATF_REQUIRE_EQ_MSG(mp_maxcpus, sysctl_maxcpus,
+	    "sanity check failed: kvm_read returned %d but sysctl maxcpus returned %d",
+	    mp_maxcpus, sysctl_maxcpus);
 }
 #endif