2 files changed, 10 insertions, 0 deletions

diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index bb7288a782fd..26bc4e2cd275 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -310,6 +310,9 @@ struct mm_struct {
 #ifdef CONFIG_MMU_NOTIFIER
         struct mmu_notifier_mm *mmu_notifier_mm;
 #endif
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+        pgtable_t pmd_huge_pte; /* protected by page_table_lock */
+#endif
         /* How many tasks sharing this mm are OOM_DISABLE */
         atomic_t oom_disable_count;
 };
diff --git a/kernel/fork.c b/kernel/fork.c
index 1499607e4da2..f78f50ba6cb2 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -529,6 +529,9 @@ void __mmdrop(struct mm_struct *mm)
         mm_free_pgd(mm);
         destroy_context(mm);
         mmu_notifier_mm_destroy(mm);
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+        VM_BUG_ON(mm->pmd_huge_pte);
+#endif
         free_mm(mm);
 }
 EXPORT_SYMBOL_GPL(__mmdrop);
@@ -669,6 +672,10 @@ struct mm_struct *dup_mm(struct task_struct *tsk)
         mm->token_priority = 0;
         mm->last_interval = 0;
 
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+        mm->pmd_huge_pte = NULL;
+#endif
+
         if (!mm_init(mm, tsk))
                 goto fail_nomem;