diff --git a/ShellPkg/Library/UefiShellDriver1CommandsLib/DrvDiag.c b/ShellPkg/Library/UefiShellDriver1CommandsLib/DrvDiag.c
index 1173f8d7be..04f6a58c3d 100644
--- a/ShellPkg/Library/UefiShellDriver1CommandsLib/DrvDiag.c
+++ b/ShellPkg/Library/UefiShellDriver1CommandsLib/DrvDiag.c
@@ -123,7 +123,7 @@ DoDiagnostics (
 
   if (ChildHandle != NULL) {
     ChildHandleList = AllocateZeroPool(2*sizeof(EFI_HANDLE));
-    if (ChildHandleList != NULL) {
+    if (ChildHandleList == NULL) {
       SHELL_FREE_NON_NULL (ControllerHandleList);
       SHELL_FREE_NON_NULL (DriverHandleList);
       return EFI_OUT_OF_RESOURCES;