diff --git a/rust/cpp_kernel/BUILD b/rust/cpp_kernel/BUILD
index 33719a85a2..a4c397c635 100644
--- a/rust/cpp_kernel/BUILD
+++ b/rust/cpp_kernel/BUILD
@@ -15,7 +15,11 @@ rust_test(
     name = "cpp_test",
     crate = ":cpp",
     tags = [
+        # TODO(b/270274576): Enable testing on arm once we have a Rust Arm toolchain.
         "not_build:arm",
+        # TODO(b/243126140): Enable tsan once we support sanitizers with Rust.
         "notsan",
+        # TODO(b/243126140): Enable msan once we support sanitizers with Rust.
+        "nomsan",
     ],
 )
diff --git a/rust/upb_kernel/BUILD b/rust/upb_kernel/BUILD
index d77b5d9ecc..8389b807b7 100644
--- a/rust/upb_kernel/BUILD
+++ b/rust/upb_kernel/BUILD
@@ -13,7 +13,9 @@ rust_test(
     name = "upb_test",
     crate = ":upb",
     tags = [
+        # TODO(b/270274576): Enable testing on arm once we have a Rust Arm toolchain.
         "not_build:arm",
+        # TODO(b/243126140): Enable tsan once we support sanitizers with Rust.
         "notsan",
         # TODO(b/243126140): Enable msan once we support sanitizers with Rust.
         "nomsan",