Index: kernel/arch/ppc32/src/mm/tlb.c
===================================================================
--- kernel/arch/ppc32/src/mm/tlb.c	(revision 6e2bf292018603bfc698dec43b84ec2c0ede62f8)
+++ kernel/arch/ppc32/src/mm/tlb.c	(revision 2d3ddada69970e73410065f93cd44b473eac1db0)
@@ -67,4 +67,6 @@
     istate_t *istate, int *pfrc)
 {
+	ASSERT(mutex_locked(&as->lock));
+
 	/*
 	 * Check if the mapping exists in page tables.