[sir_richard] 47587: [NTOS]: In MiDeleteSystemPageableVm, should also handle the case where the PTE is demand-zero. This can happen if the caller allocated, say, 12KB (3 pages) of paged pool, only touched 4KB (1 page), and then frees the allocation -- the other 2 pages will still be demand-zero at this point.

Author: sir_richard
Date: Sat Jun  5 16:54:26 2010
New Revision: 47587

URL: http://svn.reactos.org/svn/reactos?rev=47587&view=rev
Log:
[NTOS]: In MiDeleteSystemPageableVm, should also handle the case where the PTE is
demand-zero. This can happen if the caller allocated, say, 12KB (3 pages) of paged pool,
only touched 4KB (1 page), and then frees the allocation -- the other 2 pages will still
be demand-zero at this point.

Modified:
    trunk/reactos/ntoskrnl/mm/ARM3/virtual.c

Modified: trunk/reactos/ntoskrnl/mm/ARM3/virtual.c
URL:
http://svn.reactos.org/svn/reactos/trunk/reactos/ntoskrnl/mm/ARM3/virtual.c…
==============================================================================
--- trunk/reactos/ntoskrnl/mm/ARM3/virtual.c [iso-8859-1] (original)
+++ trunk/reactos/ntoskrnl/mm/ARM3/virtual.c [iso-8859-1] Sat Jun  5 16:54:26 2010
@@ -64,7 +64,6 @@
             /* As always, only handle current ARM3 scenarios */
             ASSERT(PointerPte->u.Soft.Prototype == 0);
             ASSERT(PointerPte->u.Soft.Transition == 0);
-            ASSERT(PointerPte->u.Hard.Valid == 1);
             
             /* Normally this is one possibility -- freeing a valid page */
             if (PointerPte->u.Hard.Valid)
@@ -106,6 +105,20 @@
             /* Actual legitimate pages */
             ActualPages++;
         }
+        else
+        {
+            /* 
+             * The only other ARM3 possibility is a demand zero page, which would
+             * mean freeing some of the paged pool pages that haven't even been
+             * touched yet, as part of a larger allocation.
+             *
+             * Right now, we shouldn't expect any page file information in the PTE
+             */
+             ASSERT(PointerPte->u.Soft.PageFileHigh == 0);
+             
+            /* Destroy the PTE */
+            PointerPte->u.Long = 0;
+        }
         
         /* Keep going */
         PointerPte++;