diff --git a/reactos/ntoskrnl/mm/marea.c b/reactos/ntoskrnl/mm/marea.c
index 6830f995a38..65b3c9a3e26 100644
--- a/reactos/ntoskrnl/mm/marea.c
+++ b/reactos/ntoskrnl/mm/marea.c
@@ -491,7 +491,8 @@ MmFindGapBottomUp(
 
    /* Check if there is enough space after the last memory area. */
    AlignedAddress = MM_ROUND_UP(PreviousNode->EndingAddress, Granularity);
-   if ((ULONG_PTR)HighestAddress - (ULONG_PTR)AlignedAddress >= Length)
+   if ((ULONG_PTR)HighestAddress > (ULONG_PTR)AlignedAddress &&
+       (ULONG_PTR)HighestAddress - (ULONG_PTR)AlignedAddress >= Length)
    {
       DPRINT("MmFindGapBottomUp: %p\n", AlignedAddress);
       return AlignedAddress;