diff --git a/cabal.project b/cabal.project
index 1134b0bf594..047c2efcc2a 100644
--- a/cabal.project
+++ b/cabal.project
@@ -65,6 +65,14 @@ source-repository-package
   tag: 7a0af7a8fd38045fd15fb13445bdcc7085325460
   -- https://github.com/tibbe/ekg-json/pull/12
 
+-- Needed for ghcide-bench until a new release of lsp-test is out
+source-repository-package
+  type:git
+  location: https://github.com/haskell/lsp
+  subdir: lsp-test
+  tag: c95eb06c70c35f1e13c37ed11a7d9e5b36bfa2e8
+  -- https://github.com/haskell/lsp/pull/450
+
 allow-newer:
   -- ghc-9.2
   ----------
diff --git a/ghcide-bench/src/Experiments.hs b/ghcide-bench/src/Experiments.hs
index 0a905b84547..1d8d6f6c5b4 100644
--- a/ghcide-bench/src/Experiments.hs
+++ b/ghcide-bench/src/Experiments.hs
@@ -346,7 +346,7 @@ runBenchmarksFun dir allBenchmarks = do
   results <- forM benchmarks $ \b@Bench{name} ->  do
     let p = (proc (ghcide ?config) (allArgs name dir))
                 { std_in = CreatePipe, std_out = CreatePipe, std_err = CreatePipe }
-        run sess = withCreateProcess p $ \(Just inH) (Just outH) (Just errH) _pH -> do
+        run sess = withCreateProcess p $ \(Just inH) (Just outH) (Just errH) pH -> do
                     -- Need to continuously consume to stderr else it gets blocked
                     -- Can't pass NoStream either to std_err
                     hSetBuffering errH NoBuffering
@@ -354,7 +354,7 @@ runBenchmarksFun dir allBenchmarks = do
                     let errSinkThread =
                             forever $ hGetLine errH >>= when (verbose ?config). putStrLn
                     withAsync errSinkThread $ \_ -> do
-                        runSessionWithHandles inH outH conf lspTestCaps dir sess
+                        runSessionWithHandles' (Just pH) inH outH conf lspTestCaps dir sess
     (b,) <$> runBench run b
 
   -- output raw data as CSV