diff --git a/news/8161.bugfix b/news/8161.bugfix
new file mode 100644
index 00000000000..9b4088ee296
--- /dev/null
+++ b/news/8161.bugfix
@@ -0,0 +1 @@
+Fix ``list --outdated`` and ``list --uptodate` on platforms without ``sem_open``
diff --git a/src/pip/_internal/commands/list.py b/src/pip/_internal/commands/list.py
index cf3be7eb459..555607551cc 100644
--- a/src/pip/_internal/commands/list.py
+++ b/src/pip/_internal/commands/list.py
@@ -210,17 +210,23 @@ def latest_info(dist):
                 dist.latest_filetype = typ
                 return dist
 
-            # This is done for 2x speed up of requests to pypi.org
-            # so that "real time" of this function
-            # is almost equal to "user time"
-            pool = Pool(DEFAULT_POOLSIZE)
-
-            for dist in pool.imap_unordered(latest_info, packages):
-                if dist is not None:
-                    yield dist
-
-            pool.close()
-            pool.join()
+            try:
+                # This is done for 2x speed up of requests to pypi.org
+                # so that "real time" of this function
+                # is almost equal to "user time"
+                pool = Pool(DEFAULT_POOLSIZE)
+
+                for dist in pool.imap_unordered(latest_info, packages):
+                    if dist is not None:
+                        yield dist
+
+                pool.close()
+                pool.join()
+            except ImportError:
+                for dist in packages:
+                    dist = latest_info(dist)
+                    if dist is not None:
+                        yield dist
 
     def output_package_listing(self, packages, options):
         packages = sorted(