diff --git a/src/libstore/build/hook-instance.cc b/src/libstore/build/hook-instance.cc
index cb58a1f02..ea2ae210e 100644
--- a/src/libstore/build/hook-instance.cc
+++ b/src/libstore/build/hook-instance.cc
@@ -35,7 +35,7 @@ HookInstance::HookInstance()
     /* Fork the hook. */
     pid = startProcess([&]() {
 
-        commonChildInit(fromHook);
+        commonChildInit(fromHook.writeSide.get());
 
         if (chdir("/") == -1) throw SysError("changing into /");
 
diff --git a/src/libstore/build/local-derivation-goal.cc b/src/libstore/build/local-derivation-goal.cc
index 6fb9b86e0..61c1cbccf 100644
--- a/src/libstore/build/local-derivation-goal.cc
+++ b/src/libstore/build/local-derivation-goal.cc
@@ -1649,7 +1649,7 @@ void LocalDerivationGoal::runChild()
 
     try { /* child */
 
-        commonChildInit(builderOut);
+        commonChildInit(builderOut.writeSide.get());
 
         try {
             setupSeccomp();
diff --git a/src/libutil/util.cc b/src/libutil/util.cc
index c1de4fb33..c605a33e6 100644
--- a/src/libutil/util.cc
+++ b/src/libutil/util.cc
@@ -1968,7 +1968,7 @@ std::string showBytes(uint64_t bytes)
 
 
 // FIXME: move to libstore/build
-void commonChildInit(Pipe & logPipe)
+void commonChildInit(int stderrFd)
 {
     logger = makeSimpleLogger();
 
@@ -1983,7 +1983,7 @@ void commonChildInit(Pipe & logPipe)
         throw SysError("creating a new session");
 
     /* Dup the write side of the logger pipe into stderr. */
-    if (dup2(logPipe.writeSide.get(), STDERR_FILENO) == -1)
+    if (dup2(stderrFd, STDERR_FILENO) == -1)
         throw SysError("cannot pipe standard error into log file");
 
     /* Dup stderr to stdout. */
diff --git a/src/libutil/util.hh b/src/libutil/util.hh
index 326c6b143..52ca36fd1 100644
--- a/src/libutil/util.hh
+++ b/src/libutil/util.hh
@@ -704,7 +704,7 @@ typedef std::function<bool(const Path & path)> PathFilter;
 extern PathFilter defaultPathFilter;
 
 /* Common initialisation performed in child processes. */
-void commonChildInit(Pipe & logPipe);
+void commonChildInit(int stderrFd);
 
 /* Create a Unix domain socket. */
 AutoCloseFD createUnixDomainSocket();