5 files changed, 6 insertions, 6 deletions
diff --git a/library/core/src/ffi/c_str.rs b/library/core/src/ffi/c_str.rs
index 7180593edf0..75338e492ee 100644
--- a/library/core/src/ffi/c_str.rs
+++ b/library/core/src/ffi/c_str.rs
@@ -731,7 +731,7 @@ const unsafe fn strlen(ptr: *const c_char) -> usize {
 
             len
         } else {
-            extern "C" {
+            unsafe extern "C" {
                 /// Provided by libc or compiler_builtins.
                 fn strlen(s: *const c_char) -> usize;
             }
diff --git a/library/core/src/ffi/mod.rs b/library/core/src/ffi/mod.rs
index 50968c57adc..9bae5fd466a 100644
--- a/library/core/src/ffi/mod.rs
+++ b/library/core/src/ffi/mod.rs
@@ -90,4 +90,4 @@ impl fmt::Debug for c_void {
     cfg(not(target_feature = "crt-static"))
 )]
 #[link(name = "/defaultlib:libcmt", modifiers = "+verbatim", cfg(target_feature = "crt-static"))]
-extern "C" {}
+unsafe extern "C" {}
diff --git a/library/core/src/intrinsics/mod.rs b/library/core/src/intrinsics/mod.rs
index 3b249c835f2..6c9c6d0edc2 100644
--- a/library/core/src/intrinsics/mod.rs
+++ b/library/core/src/intrinsics/mod.rs
@@ -4855,7 +4855,7 @@ pub const unsafe fn copysignf128(_x: f128, _y: f128) -> f128 {
 #[cfg(miri)]
 #[rustc_allow_const_fn_unstable(const_eval_select)]
 pub(crate) const fn miri_promise_symbolic_alignment(ptr: *const (), align: usize) {
-    extern "Rust" {
+    unsafe extern "Rust" {
         /// Miri-provided extern function to promise that a given pointer is properly aligned for
         /// "symbolic" alignment checks. Will fail if the pointer is not actually aligned or `align` is
         /// not a power of two. Has no effect when alignment checks are concrete (which is the default).
diff --git a/library/core/src/panicking.rs b/library/core/src/panicking.rs
index b97f19e1baa..d36e677d21a 100644
--- a/library/core/src/panicking.rs
+++ b/library/core/src/panicking.rs
@@ -59,7 +59,7 @@ pub const fn panic_fmt(fmt: fmt::Arguments<'_>) -> ! {
 
     // NOTE This function never crosses the FFI boundary; it's a Rust-to-Rust call
     // that gets resolved to the `#[panic_handler]` function.
-    extern "Rust" {
+    unsafe extern "Rust" {
         #[lang = "panic_impl"]
         fn panic_impl(pi: &PanicInfo<'_>) -> !;
     }
@@ -100,7 +100,7 @@ pub const fn panic_nounwind_fmt(fmt: fmt::Arguments<'_>, force_no_backtrace: boo
 
             // NOTE This function never crosses the FFI boundary; it's a Rust-to-Rust call
             // that gets resolved to the `#[panic_handler]` function.
-            extern "Rust" {
+            unsafe extern "Rust" {
                 #[lang = "panic_impl"]
                 fn panic_impl(pi: &PanicInfo<'_>) -> !;
             }
diff --git a/library/core/src/ptr/metadata.rs b/library/core/src/ptr/metadata.rs
index e93b5658e24..9eee29d485f 100644
--- a/library/core/src/ptr/metadata.rs
+++ b/library/core/src/ptr/metadata.rs
@@ -155,7 +155,7 @@ pub struct DynMetadata<Dyn: ?Sized> {
     _phantom: crate::marker::PhantomData<Dyn>,
 }
 
-extern "C" {
+unsafe extern "C" {
     /// Opaque type for accessing vtables.
     ///
     /// Private implementation detail of `DynMetadata::size_of` etc.