diff --git a/components/malloc_size_of/Cargo.toml b/components/malloc_size_of/Cargo.toml
index 69c6d4a870b..2f0db5627c5 100644
--- a/components/malloc_size_of/Cargo.toml
+++ b/components/malloc_size_of/Cargo.toml
@@ -31,7 +31,7 @@ style = { workspace = true }
 style_dom = { workspace = true }
 style_malloc_size_of = { workspace = true }
 thin-vec = { workspace = true }
-tokio = { workspace = true }
+tokio = { workspace = true, features = ["sync"] }
 url = { workspace = true }
 uuid = { workspace = true }
 webrender_api = { workspace = true }