diff --git a/Modules/posixmodule.c b/Modules/posixmodule.c
index 47b79fcc79..c8cd0d54e5 100644
--- a/Modules/posixmodule.c
+++ b/Modules/posixmodule.c
@@ -7783,11 +7783,6 @@ os_dup2_impl(PyObject *module, int fd, int fd2, int inheritable)
 /*[clinic end generated code: output=bc059d34a73404d1 input=c3cddda8922b038d]*/
 {
     int res;
-#if defined(HAVE_DUP3) && \
-    !(defined(HAVE_FCNTL_H) && defined(F_DUP2FD_CLOEXEC))
-    /* dup3() is available on Linux 2.6.27+ and glibc 2.9 */
-    int dup3_works = -1;
-#endif
 
     if (fd < 0 || fd2 < 0) {
         posix_error();
@@ -7831,38 +7826,35 @@ os_dup2_impl(PyObject *module, int fd, int fd2, int inheritable)
 #else
 
 #ifdef HAVE_DUP3
-    if (!inheritable && dup3_works != 0) {
+    if (!inheritable) {
         Py_BEGIN_ALLOW_THREADS
         res = dup3(fd, fd2, O_CLOEXEC);
         Py_END_ALLOW_THREADS
         if (res < 0) {
-            if (dup3_works == -1)
-                dup3_works = (errno != ENOSYS);
-            if (dup3_works) {
+            /* Use dup2() if dup3() fails with ENOSYS, dup3() is available on
+             * Linux 2.6.27+ and glibc 2.9. */
+            if (errno != ENOSYS) {
                 posix_error();
                 return -1;
             }
+        } else {
+            return res;
         }
     }
 
-    if (inheritable || dup3_works == 0)
-    {
 #endif
-        Py_BEGIN_ALLOW_THREADS
-        res = dup2(fd, fd2);
-        Py_END_ALLOW_THREADS
-        if (res < 0) {
-            posix_error();
-            return -1;
-        }
+    Py_BEGIN_ALLOW_THREADS
+    res = dup2(fd, fd2);
+    Py_END_ALLOW_THREADS
+    if (res < 0) {
+        posix_error();
+        return -1;
+    }
 
-        if (!inheritable && _Py_set_inheritable(fd2, 0, NULL) < 0) {
-            close(fd2);
-            return -1;
-        }
-#ifdef HAVE_DUP3
+    if (!inheritable && _Py_set_inheritable(fd2, 0, NULL) < 0) {
+        close(fd2);
+        return -1;
     }
-#endif
 
 #endif