test/canary: troubleshoot corrupt witness memory

ceno_zkvm/src/structs.rs

@@ -196,12 +196,18 @@ impl<E: ExtensionField> ZKVMFixedTraces<E> {
         input: &TC::FixedInput,
     ) {
         let cs = cs.get_cs(&TC::name()).expect("cs not found");
+        let fixed = TC::generate_fixed_traces(config, cs.num_fixed, input);
+
+        assert!(
+            fixed.all_assigned(),
+            "not all assigned in table fixed {}",
+            TC::name()
+        );
+        tracing::trace!("All assigned in table fixed {}.", TC::name());
+
         assert!(
             self.circuit_fixed_traces
-                .insert(
-                    TC::name(),
-                    Some(TC::generate_fixed_traces(config, cs.num_fixed, input)),
-                )
+                .insert(TC::name(), Some(fixed))
                 .is_none()
         );
     }
@@ -235,6 +241,14 @@ impl<E: ExtensionField> ZKVMWitnesses<E> {
         let cs = cs.get_cs(&OC::name()).unwrap();
         let (witness, logup_multiplicity) =
             OC::assign_instances(config, cs.num_witin as usize, records)?;
+
+        assert!(
+            witness.all_assigned(),
+            "not all assigned in opcode witness {}",
+            OC::name()
+        );
+        tracing::trace!("All assigned in opcode witness {}.", OC::name());
+
         assert!(self.witnesses_opcodes.insert(OC::name(), witness).is_none());
         assert!(!self.witnesses_tables.contains_key(&OC::name()));
         assert!(
@@ -287,6 +301,14 @@ impl<E: ExtensionField> ZKVMWitnesses<E> {
             self.combined_lk_mlt.as_ref().unwrap(),
             input,
         )?;
+
+        assert!(
+            witness.all_assigned(),
+            "not all assigned in table witness {}",
+            TC::name()
+        );
+        tracing::trace!("All assigned in table witness {}.", TC::name());
+
         assert!(self.witnesses_tables.insert(TC::name(), witness).is_none());
         assert!(!self.witnesses_opcodes.contains_key(&TC::name()));
 

ceno_zkvm/src/witness.rs

@@ -47,17 +47,39 @@ pub struct RowMajorMatrix<T: Sized + Sync + Clone + Send + Copy> {
     num_col: usize,
 }
 
-impl<T: Sized + Sync + Clone + Send + Copy> RowMajorMatrix<T> {
+impl<T: Sized + Sync + Clone + Send + Copy + From<u64> + Eq> RowMajorMatrix<T> {
     pub fn new(num_rows: usize, num_col: usize) -> Self {
         let num_total_rows = next_pow2_instance_padding(num_rows);
         let num_padding_rows = num_total_rows - num_rows;
-        RowMajorMatrix {
+        let mut x = RowMajorMatrix {
             values: create_uninit_vec(num_total_rows * num_col),
             num_padding_rows,
             num_col,
-        }
+        };
+
+        let c = Self::canary();
+        x.values.iter_mut().for_each(|v| *v = MaybeUninit::new(c));
+        x
+    }
+
+    pub fn all_assigned(&self) -> bool {
+        let c = Self::canary();
+        self.values
+            .iter()
+            .map(|v| {
+                let v = unsafe { v.assume_init() };
+                v != c
+            })
+            .all(|ok| ok)
     }
 
+    /// Some random value that must be overwritten.
+    fn canary() -> T {
+        T::from(8979837498374919_u64)
+    }
+}
+
+impl<T: Sized + Sync + Clone + Send + Copy> RowMajorMatrix<T> {
     pub fn num_instances(&self) -> usize {
         self.values.len() / self.num_col - self.num_padding_rows
     }