diff --git a/reactos/ntoskrnl/include/internal/mm.h b/reactos/ntoskrnl/include/internal/mm.h
index 9fcecf66a08..bccfd98a031 100644
--- a/reactos/ntoskrnl/include/internal/mm.h
+++ b/reactos/ntoskrnl/include/internal/mm.h
@@ -1574,16 +1574,14 @@ FORCEINLINE
 VOID
 MmLockAddressSpace(PMADDRESS_SPACE AddressSpace)
 {
-    KeEnterCriticalRegion();
-    ExAcquirePushLockExclusive((PEX_PUSH_LOCK)&CONTAINING_RECORD(AddressSpace, EPROCESS, VadRoot)->AddressCreationLock);
+    KeAcquireGuardedMutex(&CONTAINING_RECORD(AddressSpace, EPROCESS, VadRoot)->AddressCreationLock);
 }
 
 FORCEINLINE
 VOID
 MmUnlockAddressSpace(PMADDRESS_SPACE AddressSpace)
 {
-    ExReleasePushLock((PEX_PUSH_LOCK)&CONTAINING_RECORD(AddressSpace, EPROCESS, VadRoot)->AddressCreationLock);
-    KeLeaveCriticalRegion();
+    KeReleaseGuardedMutex(&CONTAINING_RECORD(AddressSpace, EPROCESS, VadRoot)->AddressCreationLock);
 }
 
 FORCEINLINE
diff --git a/reactos/ntoskrnl/mm/i386/page.c b/reactos/ntoskrnl/mm/i386/page.c
index 8c99a9aa2cc..c4d017baa48 100644
--- a/reactos/ntoskrnl/mm/i386/page.c
+++ b/reactos/ntoskrnl/mm/i386/page.c
@@ -196,6 +196,7 @@ MmInitializeHandBuiltProcess(IN PEPROCESS Process,
     *DirectoryTableBase = PsGetCurrentProcess()->Pcb.DirectoryTableBase;
     
     /* Initialize the Addresss Space */
+    KeInitializeGuardedMutex(&Process->AddressCreationLock);
     MmInitializeAddressSpace(Process, (PMADDRESS_SPACE)&Process->VadRoot);
     
     /* The process now has an address space */
diff --git a/reactos/ntoskrnl/mm/procsup.c b/reactos/ntoskrnl/mm/procsup.c
index 995f96b5b46..2e34da55bba 100644
--- a/reactos/ntoskrnl/mm/procsup.c
+++ b/reactos/ntoskrnl/mm/procsup.c
@@ -520,6 +520,7 @@ MmInitializeProcessAddressSpace(IN PEPROCESS Process,
     BoundaryAddressMultiple.QuadPart = 0;
 
     /* Initialize the Addresss Space */
+    KeInitializeGuardedMutex(&Process->AddressCreationLock);
     MmInitializeAddressSpace(Process, ProcessAddressSpace);
 
     /* Acquire the Lock */