diff --git a/lib/libkse/thread/thr_sigprocmask.c b/lib/libkse/thread/thr_sigprocmask.c
index ec39da009a82..9cb493a8c612 100644
--- a/lib/libkse/thread/thr_sigprocmask.c
+++ b/lib/libkse/thread/thr_sigprocmask.c
@@ -44,8 +44,10 @@ __weak_reference(_sigprocmask, sigprocmask);
 int
 _sigprocmask(int how, const sigset_t *set, sigset_t *oset)
 {
-	if (_kse_isthreaded() != 0)
-		return (pthread_sigmask(how, set, oset));
-	else
-		return (__sys_sigprocmask(how, set, oset));
+	int ret;
+
+	ret = pthread_sigmask(how, set, oset);
+	if ((ret == 0) && (_kse_isthreaded() == 0))
+		ret = __sys_sigprocmask(how, set, oset);
+	return (ret);
 }
diff --git a/lib/libpthread/thread/thr_sigprocmask.c b/lib/libpthread/thread/thr_sigprocmask.c
index ec39da009a82..9cb493a8c612 100644
--- a/lib/libpthread/thread/thr_sigprocmask.c
+++ b/lib/libpthread/thread/thr_sigprocmask.c
@@ -44,8 +44,10 @@ __weak_reference(_sigprocmask, sigprocmask);
 int
 _sigprocmask(int how, const sigset_t *set, sigset_t *oset)
 {
-	if (_kse_isthreaded() != 0)
-		return (pthread_sigmask(how, set, oset));
-	else
-		return (__sys_sigprocmask(how, set, oset));
+	int ret;
+
+	ret = pthread_sigmask(how, set, oset);
+	if ((ret == 0) && (_kse_isthreaded() == 0))
+		ret = __sys_sigprocmask(how, set, oset);
+	return (ret);
 }