MdeModulePkg DxeS3BootScriptLib: Check (mSmst != NULL) before freeing SMRAM

There is static scan tool reports BootScriptSave.c:628:'mSmst' is
explicitly dereferenced.

The patch is to check (mSmst != NULL) before freeing SMRAM at
BootScriptSave.c:628.

Cc: Shumin Qiu <shumin.qiu@intel.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Star Zeng <star.zeng@intel.com>
Reviewed-by: Shumin Qiu <shumin.qiu@intel.com>

diff --git a/MdeModulePkg/Library/PiDxeS3BootScriptLib/BootScriptSave.c b/MdeModulePkg/Library/PiDxeS3BootScriptLib/BootScriptSave.c
index f6de986e0852537ce2616566920d378331550560..0ff73211acc44a7de6aba29bc45485bca3a1b761 100644 (file)
--- a/MdeModulePkg/Library/PiDxeS3BootScriptLib/BootScriptSave.c
+++ b/MdeModulePkg/Library/PiDxeS3BootScriptLib/BootScriptSave.c
@@ -624,7 +624,7 @@ S3BootScriptLibDeinitialize (
     Status = PcdSet64S (PcdS3BootScriptTablePrivateDataPtr, 0);\r
     ASSERT_EFI_ERROR (Status);\r
   }\r
     Status = PcdSet64S (PcdS3BootScriptTablePrivateDataPtr, 0);\r
     ASSERT_EFI_ERROR (Status);\r
   }\r

-  if (mS3BootScriptTableSmmAllocated) {\r
+  if ((mSmst != NULL) && mS3BootScriptTableSmmAllocated) {\r

     Status = mSmst->SmmFreePool (mS3BootScriptTableSmmPtr);\r
     ASSERT_EFI_ERROR (Status);\r
     Status = PcdSet64S (PcdS3BootScriptTablePrivateSmmDataPtr, 0);\r
     Status = mSmst->SmmFreePool (mS3BootScriptTableSmmPtr);\r
     ASSERT_EFI_ERROR (Status);\r
     Status = PcdSet64S (PcdS3BootScriptTablePrivateSmmDataPtr, 0);\r