Index: ntoskrnl/ex/sysinfo.c
===================================================================
--- ntoskrnl/ex/sysinfo.c	(revision 72722)
+++ ntoskrnl/ex/sysinfo.c	(working copy)
@@ -812,6 +812,10 @@
         {
             SpiCurrent = (PSYSTEM_PROCESS_INFORMATION) Current;
 
+            /* Lock the Process */
+            KeEnterCriticalRegion();
+            ExAcquirePushLockExclusive(&Process->ProcessLock);
+
             if ((Process->ProcessExiting) &&
                 (Process->Pcb.Header.SignalState) &&
                 !(Process->ActiveThreads) &&
@@ -821,6 +825,10 @@
                         Process, Process->ImageFileName, Process->UniqueProcessId);
                 CurrentSize = 0;
                 ImageNameMaximumLength = 0;
+
+                /* Unlock the Process */
+                ExReleasePushLockExclusive(&Process->ProcessLock);
+                KeLeaveCriticalRegion();
                 goto Skip;
             }
 
@@ -955,6 +963,10 @@
                 ProcessImageName = NULL;
             }
 
+            /* Unlock the Process */
+            ExReleasePushLockExclusive(&Process->ProcessLock);
+            KeLeaveCriticalRegion();
+
             /* Handle idle process entry */
 Skip:
             if (Process == PsIdleProcess) Process = NULL;
Index: ntoskrnl/ps/kill.c
===================================================================
--- ntoskrnl/ps/kill.c	(revision 72722)
+++ ntoskrnl/ps/kill.c	(working copy)
@@ -421,21 +421,21 @@
     /* Make sure the thread was inserted, before continuing */
     if (!Process) return;
 
+    /* Lock the thread's process */
+    KeEnterCriticalRegion();
+    ExAcquirePushLockExclusive(&Process->ProcessLock);
+
     /* Check if the thread list is valid */
     if (Thread->ThreadListEntry.Flink)
     {
-        /* Lock the thread's process */
-        KeEnterCriticalRegion();
-        ExAcquirePushLockExclusive(&Process->ProcessLock);
-
         /* Remove us from the list */
         RemoveEntryList(&Thread->ThreadListEntry);
-
-        /* Release the lock */
-        ExReleasePushLockExclusive(&Process->ProcessLock);
-        KeLeaveCriticalRegion();
     }
 
+    /* Release the lock */
+    ExReleasePushLockExclusive(&Process->ProcessLock);
+    KeLeaveCriticalRegion();
+
     /* Dereference the Process */
     ObDereferenceObject(Process);
 }