Avoid DEBUG_CLEAR_MEMORY clearing MemoryMap internal structure.

In CoreFreePages(), the following sequence might break the MemoryMap internal structure:
CoreConvertPages() -> CoreFreeMemoryMapStack() -> AllocateMemoryMapEntry() -> CoreAllocatePoolPages() -> DEBUG_CLEAR_MEMORY()

CoreConvertPages() will call CoreFreeMemoryMapStack() after it adds the freed memory range, so the latter might use the just freed memory range when calling AllocateMemoryMapEntry(). But CoreFreePages() will call DEBUG_CLEAR_MEMORY() after CoreConvertPages(). This might clear up the memory map entry structure.

The fix calls DEBUG_CLEAR_MEMORY() just after freed memory range is added in CoreConvertPages(), which is safe.


git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@10335 6f19259b-4bc3-4df7-8a09-765794883524

1 files changed, 4 insertions, 8 deletions

diff --git a/MdeModulePkg/Core/Dxe/Mem/Page.c b/MdeModulePkg/Core/Dxe/Mem/Page.c
index b0cf1ece1..9a78698df 100644
--- a/MdeModulePkg/Core/Dxe/Mem/Page.c
+++ b/MdeModulePkg/Core/Dxe/Mem/Page.c
@@ -1,7 +1,7 @@
 /** @file

   UEFI Memory page management functions.

 

-Copyright (c) 2007 - 2008, Intel Corporation. <BR>

+Copyright (c) 2007 - 2010, Intel Corporation. <BR>

 All rights reserved. This program and the accompanying materials

 are licensed and made available under the terms and conditions of the BSD License

 which accompanies this distribution.  The full text of the license may be found at

@@ -829,6 +829,9 @@ CoreConvertPages (
     // Add our new range in

     //

     CoreAddRange (NewType, Start, RangeEnd, Attribute);

+    if (NewType == EfiConventionalMemory) {

+      DEBUG_CLEAR_MEMORY ((VOID *)(UINTN)Start, RangeEnd - Start + 1);

+    }

 

     //

     // Move any map descriptor stack to general pool

@@ -1198,13 +1201,6 @@ CoreFreePages (
     goto Done;

   }

 

-  //

-  // Destroy the contents

-  //

-  if (Memory < MAX_ADDRESS) {

-    DEBUG_CLEAR_MEMORY ((VOID *)(UINTN)Memory, NumberOfPages << EFI_PAGE_SHIFT);

-  }

-

 Done:

   CoreReleaseMemoryLock ();

   return Status;