diff --git a/changelog/2000.changed.md b/changelog/2000.changed.md
index e6b105417d..602432b850 100644
--- a/changelog/2000.changed.md
+++ b/changelog/2000.changed.md
@@ -1 +1 @@
-`mmap`, `mmap_anonymous`, `munmap`, `mremap`, `madvise`, `msync` and `mprotect` updated to use `NonNull`.
\ No newline at end of file
+`mmap`, `mmap_anonymous`, `munmap`, `mremap`, `madvise`, `msync`, `mprotect` and `munlock` updated to use `NonNull`.
\ No newline at end of file
diff --git a/src/sys/mman.rs b/src/sys/mman.rs
index 5e4acba97a..70b092441e 100644
--- a/src/sys/mman.rs
+++ b/src/sys/mman.rs
@@ -388,8 +388,8 @@ pub unsafe fn mlock(addr: *const c_void, length: size_t) -> Result<()> {
 /// page.
 ///
 /// [`munlock(2)`]: https://man7.org/linux/man-pages/man2/munlock.2.html
-pub unsafe fn munlock(addr: *const c_void, length: size_t) -> Result<()> {
-    Errno::result(libc::munlock(addr, length)).map(drop)
+pub unsafe fn munlock(addr: NonNull<c_void>, length: size_t) -> Result<()> {
+    Errno::result(libc::munlock(addr.as_ptr(), length)).map(drop)
 }
 
 /// Locks all memory pages mapped into this process' address space.