diff --git a/src/regression/sem_close-unmap.c b/src/regression/sem_close-unmap.c
new file mode 100644
index 0000000..f1e51d9
--- /dev/null
+++ b/src/regression/sem_close-unmap.c
@@ -0,0 +1,18 @@
+// commit: f70375df85d26235a45e74559afd69be59e5ff99 2020-10-28
+#define _GNU_SOURCE 1
+#include <stdlib.h>
+#include <semaphore.h>
+
+int main()
+{
+	char buf[] = "mysemXXXXXX";
+	if (!mktemp(buf)) return 1;
+	// open twice
+	sem_t *sem = sem_open(buf, O_CREAT|O_EXCL, 0600);
+	sem_open(buf, 0);
+	sem_unlink(buf);
+	// close once
+	sem_close(sem);
+	// semaphore should be still mapped
+	sem_post(sem);
+}