diff --git a/tests/sys/kern/Makefile b/tests/sys/kern/Makefile
--- a/tests/sys/kern/Makefile
+++ b/tests/sys/kern/Makefile
@@ -29,6 +29,7 @@
 ATF_TESTS_C+=	sched_affinity
 ATF_TESTS_C+=	sigaltstack
 ATF_TESTS_C+=	sigwait
+TEST_METADATA.sigwait+=	is_exclusive="true"
 .if ${MACHINE_ARCH} != "i386" && ${MACHINE_ARCH:Mpowerpc*} == ""
 ATF_TESTS_C+=	subr_physmem_test
 .endif