diff --git a/quiche/src/lib.rs b/quiche/src/lib.rs
index 4a1bde0245..b6e6122f06 100644
--- a/quiche/src/lib.rs
+++ b/quiche/src/lib.rs
@@ -3757,9 +3757,12 @@ impl Connection {
                     },
                 }
 
-                let frame = frame::Frame::Padding {
-                    len: active_path.pmtud.get_probe_size() - overhead - 1,
-                };
+                let pmtud_padding: usize = active_path
+                    .pmtud
+                    .get_probe_size()
+                    .saturating_sub(overhead + 1);
+
+                let frame = frame::Frame::Padding { len: pmtud_padding };
 
                 if push_frame_to_pkt!(b, frames, frame, left) {
                     let frame = frame::Frame::Ping {
@@ -16910,13 +16913,13 @@ mod tests {
 
         // Check that PMTU params are configured correctly
         let pmtu_param = &mut pipe.server.paths.get_mut(pid_1).unwrap().pmtud;
-        assert_eq!(pmtu_param.get_probe_status(), true);
+        assert!(pmtu_param.get_probe_status());
         assert_eq!(pmtu_param.get_probe_size(), 1350);
         assert_eq!(pipe.advance(), Ok(()));
 
         for (_, p) in pipe.server.paths.iter_mut() {
             assert_eq!(p.pmtud.get_current(), 1350);
-            assert_eq!(p.pmtud.get_probe_status(), false);
+            assert!(!p.pmtud.get_probe_status());
         }
     }
 
@@ -16970,7 +16973,7 @@ mod tests {
         assert_eq!(pmtu_param.get_current(), 1200);
 
         // Continue searching for PMTU
-        assert_eq!(pmtu_param.get_probe_status(), true);
+        assert!(pmtu_param.get_probe_status());
     }
 }