diff --git a/src/tools/tidy/src/extdeps.rs b/src/tools/tidy/src/extdeps.rs
index 8bb80f117118..2ad18f563f80 100644
--- a/src/tools/tidy/src/extdeps.rs
+++ b/src/tools/tidy/src/extdeps.rs
@@ -9,6 +9,7 @@ const ALLOWED_SOURCES: &[&str] = &[
     r#""registry+/~https://github.com/rust-lang/crates.io-index""#,
     // This is `rust_team_data` used by `site` in src/tools/rustc-perf,
     r#""git+/~https://github.com/rust-lang/team#a5260e76d3aa894c64c56e6ddc8545b9a98043ec""#,
+    r#""git+/~https://github.com/rust-lang/rustc-stable-hash?rev=refs/pull/8/head#f2780d22c5370b430fb44848c4e12c636a5fee60""#,
 ];
 
 /// Checks for external package sources. `root` is the path to the directory that contains the