diff --git a/stdlib/2and3/math.pyi b/stdlib/2and3/math.pyi
index 562ea6131..6f9a89996 100644
--- a/stdlib/2and3/math.pyi
+++ b/stdlib/2and3/math.pyi
@@ -1,5 +1,5 @@
 import sys
-from typing import Iterable, SupportsFloat, SupportsInt, Tuple, overload
+from typing import Iterable, Optional, SupportsFloat, SupportsInt, Tuple, overload
 
 e: float
 pi: float
@@ -94,6 +94,9 @@ def modf(__x: SupportsFloat) -> Tuple[float, float]: ...
 if sys.version_info >= (3, 9):
     def nextafter(__x: SupportsFloat, __y: SupportsFloat) -> float: ...
 
+if sys.version_info >= (3, 8):
+    def perm(__n: int, __k: Optional[int] = ...) -> int: ...
+
 def pow(__x: SupportsFloat, __y: SupportsFloat) -> float: ...
 
 if sys.version_info >= (3, 8):
diff --git a/stdlib/3/gzip.pyi b/stdlib/3/gzip.pyi
index 6d9fef73e..4ce54b3b8 100644
--- a/stdlib/3/gzip.pyi
+++ b/stdlib/3/gzip.pyi
@@ -43,6 +43,9 @@ class _PaddedFile:
     def seek(self, off: int) -> int: ...
     def seekable(self) -> bool: ...
 
+if sys.version_info >= (3, 8):
+    class BadGzipFile(OSError): ...
+
 class GzipFile(_compression.BaseStream):
     myfileobj: Optional[IO[bytes]]
     mode: str