[cgutman] 54579: [NTOSKRNL] - Release the address space lock before entering SEH because an exception would result in recursive acquisition of the address space lock when the fault handler tries to...

Author: cgutman
Date: Sun Dec  4 08:25:35 2011
New Revision: 54579
URL: http://svn.reactos.org/svn/reactos?rev=54579&view=rev
Log:
[NTOSKRNL]
- Release the address space lock before entering SEH because an exception would result in
recursive acquisition of the address space lock when the fault handler tries to grab it
Modified:
    trunk/reactos/ntoskrnl/mm/anonmem.c
Modified: trunk/reactos/ntoskrnl/mm/anonmem.c
URL:
http://svn.reactos.org/svn/reactos/trunk/reactos/ntoskrnl/mm/anonmem.c?rev=…
==============================================================================
--- trunk/reactos/ntoskrnl/mm/anonmem.c [iso-8859-1] (original)
+++ trunk/reactos/ntoskrnl/mm/anonmem.c [iso-8859-1] Sun Dec  4 08:25:35 2011
@@ -1004,8 +1004,8 @@
     NTSTATUS Status;
     PEPROCESS Process;
     PMMSUPPORT AddressSpace;
-    PVOID BaseAddress, PBaseAddress;
-    SIZE_T RegionSize, PRegionSize;
+    PVOID BaseAddress = NULL, PBaseAddress;
+    SIZE_T RegionSize = 0, PRegionSize;
     PEPROCESS CurrentProcess = PsGetCurrentProcess();
     KPROCESSOR_MODE PreviousMode = KeGetPreviousMode();
     KAPC_STATE ApcState;
@@ -1183,22 +1183,26 @@
         goto unlock_deref_and_return;
     }
-    /* Enter SEH */
-    _SEH2_TRY
-    {
-        /* Copy rounded values back in success case */
-        *UBaseAddress = BaseAddress;
-        *URegionSize = RegionSize;
-    }
-    _SEH2_EXCEPT(EXCEPTION_EXECUTE_HANDLER)
-    {
-        Status = _SEH2_GetExceptionCode();
-        DPRINT1("Failed to copy values back! (Status: 0x%x)\n", Status);
-    }
-    _SEH2_END;
-
 unlock_deref_and_return:
     MmUnlockAddressSpace(AddressSpace);
+
+    /* Copy rounded values back in success case */
+    if (NT_SUCCESS(Status))
+    {
+        /* Enter SEH */
+        _SEH2_TRY
+        {
+            *UBaseAddress = BaseAddress;
+            *URegionSize = RegionSize;
+        }
+        _SEH2_EXCEPT(EXCEPTION_EXECUTE_HANDLER)
+        {
+            Status = _SEH2_GetExceptionCode();
+            DPRINT1("Failed to copy values back! (Status: 0x%x)\n", Status);
+        }
+        _SEH2_END;
+    }
+
     if (Attached) KeUnstackDetachProcess(&ApcState);
     if (ProcessHandle != NtCurrentProcess()) ObDereferenceObject(Process);