diff --git a/Cargo.toml b/Cargo.toml
index a45a969..70af365 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -16,4 +16,4 @@ rustdoc-args = ["--cfg", "docsrs"]
 fam-wrappers = ["vmm-sys-util"]
 
 [dependencies]
-vmm-sys-util = { version = "0.11.0", optional = true }
+vmm-sys-util = { version = "0.12.1", optional = true }
diff --git a/src/x86_64/fam_wrappers.rs b/src/x86_64/fam_wrappers.rs
index b659e0e..032879d 100644
--- a/src/x86_64/fam_wrappers.rs
+++ b/src/x86_64/fam_wrappers.rs
@@ -120,10 +120,15 @@ mod tests {
 
         let mut wrapper2 = wrapper.clone();
         assert!(wrapper == wrapper2);
-
-        wrapper.as_mut_fam_struct().pad = 1;
+        // SAFETY: We are not modifying the `nmsrs` field
+        unsafe {
+            wrapper.as_mut_fam_struct().pad = 1;
+        }
         assert!(wrapper != wrapper2);
-        wrapper2.as_mut_fam_struct().pad = 1;
+        // SAFETY: We are not modifying the `nmsrs` field
+        unsafe {
+            wrapper2.as_mut_fam_struct().pad = 1;
+        }
         assert!(wrapper == wrapper2);
 
         wrapper.as_mut_slice()[1].data = 1;