diff --git a/tests/run-pass-fullmir/send-is-not-static-par-for.rs b/tests/run-pass-fullmir/send-is-not-static-par-for.rs
index 1b913aed4c89..282f7a359503 100644
--- a/tests/run-pass-fullmir/send-is-not-static-par-for.rs
+++ b/tests/run-pass-fullmir/send-is-not-static-par-for.rs
@@ -8,6 +8,9 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+// FIXME: Still investigating whether there is UB here
+// compile-flags: -Zmiri-disable-validation
+
 use std::sync::Mutex;
 
 fn par_for<I, F>(iter: I, f: F)
diff --git a/tests/run-pass-fullmir/u128.rs b/tests/run-pass-fullmir/u128.rs
index ca33bd5f9e3d..0f1b6e8b5870 100644
--- a/tests/run-pass-fullmir/u128.rs
+++ b/tests/run-pass-fullmir/u128.rs
@@ -8,6 +8,9 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+// FIXME: Still investigating whether there is UB here
+// compile-flags: -Zmiri-disable-validation
+
 fn b<T>(t: T) -> T { t }
 
 fn main() {
diff --git a/tests/run-pass-fullmir/vecdeque.rs b/tests/run-pass-fullmir/vecdeque.rs
index 381169505ec9..ffbb11668498 100644
--- a/tests/run-pass-fullmir/vecdeque.rs
+++ b/tests/run-pass-fullmir/vecdeque.rs
@@ -1,3 +1,6 @@
+// FIXME: Still investigating whether there is UB here
+// compile-flags: -Zmiri-disable-validation
+
 use std::collections::VecDeque;
 
 fn main() {