diff --git a/drivers/usb/gadget/function/f_fs.c b/drivers/usb/gadget/function/f_fs.c
index 002c3441bea3..815639506520 100644
--- a/drivers/usb/gadget/function/f_fs.c
+++ b/drivers/usb/gadget/function/f_fs.c
@@ -619,7 +619,7 @@ static ssize_t ffs_ep0_read(struct file *file, char __user *buf,
 
 		/* unlocks spinlock */
 		ret = __ffs_ep0_queue_wait(ffs, data, len);
-		if ((ret > 0) && (copy_to_user(buf, data, len)))
+		if ((ret > 0) && (copy_to_user(buf, data, ret)))
 			ret = -EFAULT;
 		goto done_mutex;