1 files changed, 28 insertions, 0 deletions
diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c
index 4c78458ea78d..b676575f2268 100644
--- a/fs/userfaultfd.c
+++ b/fs/userfaultfd.c
@@ -774,6 +774,34 @@ void userfaultfd_unmap_complete(struct mm_struct *mm, struct list_head *uf)
 	}
 }
 
+void userfaultfd_exit(struct mm_struct *mm)
+{
+	struct vm_area_struct *vma = mm->mmap;
+
+	/*
+	 * We can do the vma walk without locking because the caller
+	 * (exit_mm) knows it now has exclusive access
+	 */
+	while (vma) {
+		struct userfaultfd_ctx *ctx = vma->vm_userfaultfd_ctx.ctx;
+
+		if (ctx && (ctx->features & UFFD_FEATURE_EVENT_EXIT)) {
+			struct userfaultfd_wait_queue ewq;
+
+			userfaultfd_ctx_get(ctx);
+
+			msg_init(&ewq.msg);
+			ewq.msg.event = UFFD_EVENT_EXIT;
+
+			userfaultfd_event_wait_completion(ctx, &ewq);
+
+			ctx->features &= ~UFFD_FEATURE_EVENT_EXIT;
+		}
+
+		vma = vma->vm_next;
+	}
+}
+
 static int userfaultfd_release(struct inode *inode, struct file *file)
 {
 	struct userfaultfd_ctx *ctx = file->private_data;