[PATCH] MdeModulePkg/UefiBootManagerLib: Initialize Handle before using it

[Ruiyu Ni <ruiyu.ni@intel.com>]

BmExpandMediaDevicePath contains a bug that it uses the
uninitialized Handle.

Since the function is called when the Handle supports BlockIo
or SimpleFileSystem, when there is no SimpleFileSystem installed
on the Handle, BlockIo should be installed on the Handle.
The fix initializes the Handle by locating the BlockIo protocol
from the device path.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Ruiyu Ni <ruiyu.ni@intel.com>
Cc: Jeff Fan <jeff.fan@intel.com>
---
 MdeModulePkg/Library/UefiBootManagerLib/BmBoot.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/MdeModulePkg/Library/UefiBootManagerLib/BmBoot.c b/MdeModulePkg/Library/UefiBootManagerLib/BmBoot.c
index 75bd5dc..9f99122 100644
--- a/MdeModulePkg/Library/UefiBootManagerLib/BmBoot.c
+++ b/MdeModulePkg/Library/UefiBootManagerLib/BmBoot.c
@@ -991,9 +991,13 @@ BmExpandMediaDevicePath (
     return FileBuffer;
   }
 
+  Status = gBS->LocateDevicePath (&gEfiBlockIoProtocolGuid, &TempDevicePath, &Handle);
+  ASSERT_EFI_ERROR (Status);
+
   //
   // For device boot option only pointing to the removable device handle, 
-  // should make sure all its children handles (its child partion or media handles) are created and connected. 
+  // should make sure all its children handles (its child partion or media handles)
+  // are created and connected. 
   //
   gBS->ConnectController (Handle, NULL, NULL, TRUE);
 
@@ -1004,8 +1008,6 @@ BmExpandMediaDevicePath (
   // returned. After the Block IO protocol is reinstalled, subsequent
   // Block IO read/write will success.
   //
-  Status = gBS->LocateDevicePath (&gEfiBlockIoProtocolGuid, &TempDevicePath, &Handle);
-  ASSERT_EFI_ERROR (Status);
   Status = gBS->HandleProtocol (Handle, &gEfiBlockIoProtocolGuid, (VOID **) &BlockIo);
   ASSERT_EFI_ERROR (Status);
   Buffer = AllocatePool (BlockIo->Media->BlockSize);
-- 
2.9.0.windows.1