diff --git a/drivers/usb/gadget/legacy/inode.c b/drivers/usb/gadget/legacy/inode.c index d87a8ab51510..db961aaa3740 100644 --- a/drivers/usb/gadget/legacy/inode.c +++ b/drivers/usb/gadget/legacy/inode.c @@ -471,11 +471,17 @@ static void ep_user_copy_worker(struct work_struct *work) struct kiocb *iocb = priv->iocb; size_t ret; - kthread_use_mm(mm); - ret = copy_to_iter(priv->buf, priv->actual, &priv->to); - kthread_unuse_mm(mm); - if (!ret) + if (mmget_not_zero(mm)) { + kthread_use_mm(mm); + ret = copy_to_iter(priv->buf, priv->actual, &priv->to); + kthread_unuse_mm(mm); + mmput(mm); + if (!ret) + ret = -EFAULT; + } else { ret = -EFAULT; + } + mmdrop(mm); /* completing the iocb can drop the ctx and mm, don't touch mm after */ iocb->ki_complete(iocb, ret); @@ -501,6 +507,7 @@ static void ep_aio_complete(struct usb_ep *ep, struct usb_request *req) * complete the aio request immediately. */ if (priv->to_free == NULL || unlikely(req->actual == 0)) { + mmdrop(priv->mm); kfree(req->buf); kfree(priv->to_free); kfree(priv); @@ -541,6 +548,7 @@ static ssize_t ep_aio(struct kiocb *iocb, priv->epdata = epdata; priv->actual = 0; priv->mm = current->mm; /* mm teardown waits for iocbs in exit_aio() */ + mmgrab(priv->mm); /* each kiocb is coupled to one usb_request, but we can't * allocate or submit those if the host disconnected. @@ -570,6 +578,7 @@ static ssize_t ep_aio(struct kiocb *iocb, fail: spin_unlock_irq(&epdata->dev->lock); + mmdrop(priv->mm); kfree(priv->to_free); kfree(priv); put_ep(epdata);