diff --git a/src/system_wrappers/source/cpu_linux.cc b/src/system_wrappers/source/cpu_linux.cc
index 9d7d89de64..8e8ecda6ca 100644
--- a/src/system_wrappers/source/cpu_linux.cc
+++ b/src/system_wrappers/source/cpu_linux.cc
@@ -179,6 +179,7 @@ int CpuLinux::GetNumCores()
     char line[100];
     if (!fgets(line, 100, fp))
     {
+        fclose(fp);
         return -1;
     }
     int numCores = -1;