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mockprover error hint #270

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merged 2 commits into from
Oct 10, 2024
Merged

mockprover error hint #270

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576b33d
mockprover error hint
hero78119 Sep 23, 2024
fc41e08
Merge branch 'master' into feat/mock_prover_hint_msg
matthiasgoergens Oct 10, 2024
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9 changes: 9 additions & 0 deletions ceno_zkvm/src/scheme/mock_prover.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -481,6 +481,15 @@ impl<'a, E: ExtensionField + Hash> MockProver<E> {
println!("======================================================");
println!("Error: {} constraints not satisfied", errors.len());

println!(
r"Hints:
- If you encounter a constraint error that sporadically occurs in different environments
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That sounds like we need to tighten up our constraints? Otherwise, a malicious prover might be able to exploit the UB?

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That sounds like we need to tighten up our constraints? Otherwise, a malicious prover might be able to exploit the UB?

It not related to constraints :) This problem just related to the witnesses where we assuming them to be zero and skip their assignment, but actually unassigned witnesses is "undefined behaviour" due to we enclosed MaybeUint when allocated vector.

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Oh, that makes sense.

Btw, why do we do these shenanigans? Have we done a benchmark to check whether MaybeUninit actually helps us?

(e.g., passes locally but fails in CI),
this often points to unassigned witnesses during the assignment phase.
Accessing these cells before they are properly written leads to undefined behavior.
"
);

for error in errors {
error.print(wits_in, &cb.cs.witin_namespace_map);
}
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