diff --git a/kernel/fork.c b/kernel/fork.c
index ac8100e3088a1f6d99d8ad640a70a3de5ec96e5e..195958a3a4d6ff0405ed8dcf019cecfddfb363fb 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -368,6 +368,8 @@ void fastcall __mmdrop(struct mm_struct *mm)
  */
 void mmput(struct mm_struct *mm)
 {
+	might_sleep();
+
 	if (atomic_dec_and_test(&mm->mm_users)) {
 		exit_aio(mm);
 		exit_mmap(mm);