[ros-diffs] [tkreuzer] 50804: [WIN32K] Fix a bug in GDIOBJ_LockObj, that would cause a deadlock, when an object was deleted while another thread was waiting to acquire the handle lock.

Author: tkreuzer
Date: Fri Feb 18 15:08:50 2011
New Revision: 50804

URL: http://svn.reactos.org/svn/reactos?rev=50804&view=rev
Log:
[WIN32K]
Fix a bug in GDIOBJ_LockObj, that would cause a deadlock, when an object was deleted while another thread was waiting to acquire the handle lock.

Modified:
    trunk/reactos/subsystems/win32/win32k/objects/gdiobj.c

Modified: trunk/reactos/subsystems/win32/win32k/objects/gdiobj.c
URL: http://svn.reactos.org/svn/reactos/trunk/reactos/subsystems/win32/win32k/obj...
==============================================================================
--- trunk/reactos/subsystems/win32/win32k/objects/gdiobj.c [iso-8859-1] (original)
+++ trunk/reactos/subsystems/win32/win32k/objects/gdiobj.c [iso-8859-1] Fri Feb 18 15:08:50 2011
@@ -1005,16 +1005,6 @@
     }

ProcessId = (HANDLE)((ULONG_PTR)PsGetCurrentProcessId() & ~1);
-    HandleProcessId = (HANDLE)((ULONG_PTR)Entry->ProcessId & ~1);
-
-    /* Check for invalid owner. */
-    if (ProcessId != HandleProcessId && HandleProcessId != NULL)
-    {
-        DPRINT1("Tried to lock object (0x%p) of wrong owner! ProcessId = %p, HandleProcessId = %p\n", hObj, ProcessId, HandleProcessId);
-        GDIDBG_TRACECALLER();
-        GDIDBG_TRACEALLOCATOR(hObj);
-        return NULL;
-    }

/*
      * Prevent the thread from being terminated during the locking process.
@@ -1031,6 +1021,17 @@

for (;;)
     {
+        HandleProcessId = (HANDLE)((ULONG_PTR)Entry->ProcessId & ~1);
+
+        /* Check for invalid owner. */
+        if (ProcessId != HandleProcessId && HandleProcessId != NULL)
+        {
+            DPRINT1("Tried to lock object (0x%p) of wrong owner! ProcessId = %p, HandleProcessId = %p\n", hObj, ProcessId, HandleProcessId);
+            GDIDBG_TRACECALLER();
+            GDIDBG_TRACEALLOCATOR(hObj);
+            break;
+        }
+
         /* Lock the handle table entry. */
         LockedProcessId = (HANDLE)((ULONG_PTR)HandleProcessId | 0x1);
         PrevProcId = InterlockedCompareExchangePointer((PVOID*)&Entry->ProcessId,