diff --git a/tornado/iostream.py b/tornado/iostream.py
index 53e81fff3..89814c0b6 100644
--- a/tornado/iostream.py
+++ b/tornado/iostream.py
@@ -346,7 +346,7 @@ def read_until_regex(
             gen_log.info("Unsatisfiable read, closing connection: %s" % e)
             self.close(exc_info=e)
             return future
-        except:
+        except Exception:
             # Ensure that the future doesn't log an error because its
             # failure was never examined.
             future.add_done_callback(lambda f: f.exception())
@@ -383,7 +383,7 @@ def read_until(
             gen_log.info("Unsatisfiable read, closing connection: %s" % e)
             self.close(exc_info=e)
             return future
-        except:
+        except Exception:
             future.add_done_callback(lambda f: f.exception())
             raise
         return future
@@ -411,7 +411,7 @@ def read_bytes(self, num_bytes: int, partial: bool = False) -> Awaitable[bytes]:
         self._read_partial = partial
         try:
             self._try_inline_read()
-        except:
+        except Exception:
             future.add_done_callback(lambda f: f.exception())
             raise
         return future
@@ -456,7 +456,7 @@ def read_into(self, buf: bytearray, partial: bool = False) -> Awaitable[int]:
 
         try:
             self._try_inline_read()
-        except:
+        except Exception:
             future.add_done_callback(lambda f: f.exception())
             raise
         return future
@@ -486,7 +486,7 @@ def read_until_close(self) -> Awaitable[bytes]:
         self._read_until_close = True
         try:
             self._try_inline_read()
-        except:
+        except Exception:
             future.add_done_callback(lambda f: f.exception())
             raise
         return future