Issue #21090: io.FileIO.readall() does not ignore I/O errors anymore. Before,
it ignored I/O errors if at least the first C call read() succeed.
diff --git a/Misc/NEWS b/Misc/NEWS
index ddd2e0b..6f266ab 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -13,6 +13,9 @@
 Library
 -------
 
+- Issue #21090: io.FileIO.readall() does not ignore I/O errors anymore. Before,
+  it ignored I/O errors if at least the first C call read() succeed.
+
 - Issue #19870: BaseCookie now parses 'secure' and 'httponly' flags.
   Backport of issue #16611.