diff --git a/library/core/src/ffi/mod.rs b/library/core/src/ffi/mod.rs
index b2c9a0800c91b..6908c824f44b6 100644
--- a/library/core/src/ffi/mod.rs
+++ b/library/core/src/ffi/mod.rs
@@ -6,7 +6,7 @@
 //! match those defined by C, so that code that interacts with C will
 //! refer to the correct types.
 
-#![stable(feature = "", since = "1.30.0")]
+#![stable(feature = "core_ffi", since = "1.30.0")]
 #![allow(non_camel_case_types)]
 
 use crate::fmt;
diff --git a/library/std/src/io/mod.rs b/library/std/src/io/mod.rs
index e6431abcf8215..56b1664b60081 100644
--- a/library/std/src/io/mod.rs
+++ b/library/std/src/io/mod.rs
@@ -1140,10 +1140,10 @@ pub fn read_to_string<R: Read>(mut reader: R) -> Result<String> {
 #[repr(transparent)]
 pub struct IoSliceMut<'a>(sys::io::IoSliceMut<'a>);
 
-#[stable(feature = "iovec-send-sync", since = "1.44.0")]
+#[stable(feature = "iovec_send_sync", since = "1.44.0")]
 unsafe impl<'a> Send for IoSliceMut<'a> {}
 
-#[stable(feature = "iovec-send-sync", since = "1.44.0")]
+#[stable(feature = "iovec_send_sync", since = "1.44.0")]
 unsafe impl<'a> Sync for IoSliceMut<'a> {}
 
 #[stable(feature = "iovec", since = "1.36.0")]
@@ -1283,10 +1283,10 @@ impl<'a> DerefMut for IoSliceMut<'a> {
 #[repr(transparent)]
 pub struct IoSlice<'a>(sys::io::IoSlice<'a>);
 
-#[stable(feature = "iovec-send-sync", since = "1.44.0")]
+#[stable(feature = "iovec_send_sync", since = "1.44.0")]
 unsafe impl<'a> Send for IoSlice<'a> {}
 
-#[stable(feature = "iovec-send-sync", since = "1.44.0")]
+#[stable(feature = "iovec_send_sync", since = "1.44.0")]
 unsafe impl<'a> Sync for IoSlice<'a> {}
 
 #[stable(feature = "iovec", since = "1.36.0")]