diff --git a/ntoskrnl/include/internal/ke_x.h b/ntoskrnl/include/internal/ke_x.h
index 70fa05e1d12..fcf3edb2786 100644
--- a/ntoskrnl/include/internal/ke_x.h
+++ b/ntoskrnl/include/internal/ke_x.h
@@ -1359,6 +1359,7 @@ KxQueueReadyThread(IN PKTHREAD Thread,
 
     /* Sanity checks */
     ASSERT(Prcb == KeGetCurrentPrcb());
+    ASSERT(Prcb->PrcbLock != 0);
     ASSERT(Thread->State == Running);
     ASSERT(Thread->NextProcessor == Prcb->Number);
 
diff --git a/ntoskrnl/ke/arm/thrdini.c b/ntoskrnl/ke/arm/thrdini.c
index 190b73f926c..c32b39c392d 100644
--- a/ntoskrnl/ke/arm/thrdini.c
+++ b/ntoskrnl/ke/arm/thrdini.c
@@ -334,6 +334,9 @@ KiDispatchInterrupt(VOID)
     }
     else if (Prcb->NextThread)
     {
+        /* Acquire the PRCB lock */
+        KiAcquirePrcbLock(Prcb);
+
         /* Capture current thread data */
         OldThread = Prcb->CurrentThread;
         NewThread = Prcb->NextThread;
diff --git a/ntoskrnl/ke/i386/thrdini.c b/ntoskrnl/ke/i386/thrdini.c
index 3214f560872..91e8ad3931f 100644
--- a/ntoskrnl/ke/i386/thrdini.c
+++ b/ntoskrnl/ke/i386/thrdini.c
@@ -495,6 +495,9 @@ KiDispatchInterrupt(VOID)
     }
     else if (Prcb->NextThread)
     {
+        /* Acquire the PRCB lock */
+        KiAcquirePrcbLock(Prcb);
+
         /* Capture current thread data */
         OldThread = Prcb->CurrentThread;
         NewThread = Prcb->NextThread;