diff --git a/src/libutil/util.cc b/src/libutil/util.cc
index 6c7f93d50..bc841f425 100644
--- a/src/libutil/util.cc
+++ b/src/libutil/util.cc
@@ -1716,6 +1716,8 @@ string showBytes(uint64_t bytes)
 // FIXME: move to libstore/build
 void commonChildInit(Pipe & logPipe)
 {
+    logger = makeSimpleLogger();
+
     const static string pathNullDevice = "/dev/null";
     restoreProcessContext();
 
diff --git a/tests/ca/signatures.sh b/tests/ca/signatures.sh
index 4b4e468f7..0c7d974ea 100644
--- a/tests/ca/signatures.sh
+++ b/tests/ca/signatures.sh
@@ -22,8 +22,8 @@ testOneCopy () {
     rm -rf "$REMOTE_STORE_DIR"
 
     attrPath="$1"
-    nix copy --to $REMOTE_STORE "$attrPath" --file ./content-addressed.nix \
-        --secret-key-files "$TEST_ROOT/sk1"
+    nix copy -vvvv --to $REMOTE_STORE "$attrPath" --file ./content-addressed.nix \
+        --secret-key-files "$TEST_ROOT/sk1" --show-trace
 
     ensureCorrectlyCopied "$attrPath"