diff --git a/easybuild/tools/run.py b/easybuild/tools/run.py
index 4f83acd9c3..c327930a8d 100644
--- a/easybuild/tools/run.py
+++ b/easybuild/tools/run.py
@@ -514,9 +514,12 @@ def to_cmd_str(cmd):
 
         if qa_patterns:
             # make stdout, stderr, stdin non-blocking files
-            channels = [proc.stdout, proc.stdin]
+            channels = [proc.stdout]
+            if stdin:
+                channels.append(proc.stdin)
             if split_stderr:
-                channels += proc.stderr
+                channels.append(proc.stderr)
+
             for channel in channels:
                 fd = channel.fileno()
                 flags = fcntl.fcntl(fd, fcntl.F_GETFL)