MdeModulePkg DxeCore: Avoid the closed event to be signaled wrongly

Signal a closed event will still invoke the event notification function,
it could only be exposed when no the DEBUG_PROPERTY_CLEAR_MEMORY_ENABLED
bit set in PcdDebugPropertyMask.

For example:
  gBS->CreateEvent (
                EVT_NOTIFY_SIGNAL,
                TPL_CALLBACK,
                CallbackFun,
                NULL,
                &Event
                );
  gBS->CloseEvent (Event);
  gBS->SignalEvent (Event);      <- CallbackFun still be invoked

Although the case to signal a closed event is abnormal, the code could
still be enhanced to avoid it.

Cc: Liming Gao <liming.gao@intel.com>
Cc: Feng Tian <feng.tian@intel.com>
Cc: Thomas Palmer <thomas.palmer@hpe.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Star Zeng <star.zeng@intel.com>
Reviewed-by: Liming Gao <liming.gao@intel.com>

git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@19754 6f19259b-4bc3-4df7-8a09-765794883524

1 files changed, 6 insertions, 1 deletions

diff --git a/MdeModulePkg/Core/Dxe/Event/Event.c b/MdeModulePkg/Core/Dxe/Event/Event.c
index 34b34ac62f..01715ec3ca 100644
--- a/MdeModulePkg/Core/Dxe/Event/Event.c
+++ b/MdeModulePkg/Core/Dxe/Event/Event.c
@@ -1,7 +1,7 @@
 /** @file

   UEFI Event support functions implemented in this file.

 

-Copyright (c) 2006 - 2014, Intel Corporation. All rights reserved.<BR>

+Copyright (c) 2006 - 2016, Intel Corporation. All rights reserved.<BR>

 (C) Copyright 2015 Hewlett Packard Enterprise Development LP<BR>

 This program and the accompanying materials

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

@@ -769,6 +769,11 @@ CoreCloseEvent (
     CoreUnregisterProtocolNotify (Event);

   }

 

+  //

+  // To avoid the Event to be signalled wrongly after closed,

+  // clear the Signature of Event before free pool.

+  //

+  Event->Signature = 0;

   Status = CoreFreePool (Event);

   ASSERT_EFI_ERROR (Status);