Handling null ptr in NtFreeVirtualMemory.

src/xenia/kernel/modules/xboxkrnl/xboxkrnl_memory.cc

@@ -121,6 +121,11 @@ SHIM_CALL NtFreeVirtualMemory_shim(
       region_size_ptr, region_size_value,
       free_type, unknown);
 
+  if (!base_addr_value) {
+    SHIM_SET_RETURN(X_STATUS_MEMORY_NOT_ALLOCATED);
+    return;
+  }
+
   // Free.
   uint32_t flags = 0;
   uint32_t freed_size = xe_memory_heap_free(state->memory(), base_addr_value,

src/xenia/kernel/xbox.h

@@ -41,6 +41,7 @@ typedef uint32_t X_STATUS;
 #define X_STATUS_BUFFER_TOO_SMALL                       ((uint32_t)0xC0000023L)
 #define X_STATUS_OBJECT_TYPE_MISMATCH                   ((uint32_t)0xC0000024L)
 #define X_STATUS_INVALID_PAGE_PROTECTION                ((uint32_t)0xC0000045L)
+#define X_STATUS_MEMORY_NOT_ALLOCATED                   ((uint32_t)0xC00000A0L)
 
 
 // MEM_*, used by NtAllocateVirtualMemory