diff --git a/std/src/sys/pal/teeos/alloc.rs b/std/src/sys/pal/teeos/alloc.rs
index e236819aa2388..b280d1dd76f7a 100644
--- a/std/src/sys/pal/teeos/alloc.rs
+++ b/std/src/sys/pal/teeos/alloc.rs
@@ -11,9 +11,9 @@ unsafe impl GlobalAlloc for System {
         // Also see <https://github.com/rust-lang/rust/issues/45955> and
         // <https://github.com/rust-lang/rust/issues/62251#issuecomment-507580914>.
         if layout.align() <= MIN_ALIGN && layout.align() <= layout.size() {
-            libc::malloc(layout.size()) as *mut u8
+            unsafe { libc::malloc(layout.size()) as *mut u8 }
         } else {
-            aligned_malloc(&layout)
+            unsafe { aligned_malloc(&layout) }
         }
     }
 
@@ -21,11 +21,11 @@ unsafe impl GlobalAlloc for System {
     unsafe fn alloc_zeroed(&self, layout: Layout) -> *mut u8 {
         // See the comment above in `alloc` for why this check looks the way it does.
         if layout.align() <= MIN_ALIGN && layout.align() <= layout.size() {
-            libc::calloc(layout.size(), 1) as *mut u8
+            unsafe { libc::calloc(layout.size(), 1) as *mut u8 }
         } else {
-            let ptr = self.alloc(layout);
+            let ptr = unsafe { self.alloc(layout) };
             if !ptr.is_null() {
-                ptr::write_bytes(ptr, 0, layout.size());
+                unsafe { ptr::write_bytes(ptr, 0, layout.size()) };
             }
             ptr
         }
@@ -33,15 +33,15 @@ unsafe impl GlobalAlloc for System {
 
     #[inline]
     unsafe fn dealloc(&self, ptr: *mut u8, _layout: Layout) {
-        libc::free(ptr as *mut libc::c_void)
+        unsafe { libc::free(ptr as *mut libc::c_void) }
     }
 
     #[inline]
     unsafe fn realloc(&self, ptr: *mut u8, layout: Layout, new_size: usize) -> *mut u8 {
         if layout.align() <= MIN_ALIGN && layout.align() <= new_size {
-            libc::realloc(ptr as *mut libc::c_void, new_size) as *mut u8
+            unsafe { libc::realloc(ptr as *mut libc::c_void, new_size) as *mut u8 }
         } else {
-            realloc_fallback(self, ptr, layout, new_size)
+            unsafe { realloc_fallback(self, ptr, layout, new_size) }
         }
     }
 }
@@ -52,6 +52,6 @@ unsafe fn aligned_malloc(layout: &Layout) -> *mut u8 {
     // posix_memalign requires that the alignment be a multiple of `sizeof(void*)`.
     // Since these are all powers of 2, we can just use max.
     let align = layout.align().max(crate::mem::size_of::<usize>());
-    let ret = libc::posix_memalign(&mut out, align, layout.size());
+    let ret = unsafe { libc::posix_memalign(&mut out, align, layout.size()) };
     if ret != 0 { ptr::null_mut() } else { out as *mut u8 }
 }