replace "glink" by "ctrl" in subject On 9/12/22 19:05, Deepak Kumar Singh wrote: > Call to rpmsg_ctrldev_ioctl() and rpmsg_ctrldev_remove() must be synchronized. > In present code rpmsg_ctrldev_remove() is not protected with lock, therefore > new char device creation can succeed through rpmsg_ctrldev_ioctl() call. At the > same time call to rpmsg_ctrldev_remove() funtion for ctrl device removal will > free associated rpdev device. As char device creation already succeeded, user > space is free to issue open() call which maps to rpmsg_create_ept() in kernel. > rpmsg_create_ept() function tries to reference rpdev which has already been > freed through rpmsg_ctrldev_remove(). Issue is predominantly seen in aggressive > reboot tests where rpmsg_ctrldev_ioctl() and rpmsg_ctrldev_remove() can race with > each other. > > Adding lock in rpmsg_ctrldev_remove() avoids any new char device creation > throught rpmsg_ctrldev_ioctl() while remove call is already in progress. > > Signed-off-by: Deepak Kumar Singh <quic_deesin@xxxxxxxxxxx> > --- > drivers/rpmsg/rpmsg_ctrl.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/drivers/rpmsg/rpmsg_ctrl.c b/drivers/rpmsg/rpmsg_ctrl.c > index 107da70..4332538 100644 > --- a/drivers/rpmsg/rpmsg_ctrl.c > +++ b/drivers/rpmsg/rpmsg_ctrl.c > @@ -194,10 +194,12 @@ static void rpmsg_ctrldev_remove(struct rpmsg_device *rpdev) > struct rpmsg_ctrldev *ctrldev = dev_get_drvdata(&rpdev->dev); > int ret; > > + mutex_lock(&ctrldev->ctrl_lock); > /* Destroy all endpoints */ > ret = device_for_each_child(&ctrldev->dev, NULL, rpmsg_chrdev_eptdev_destroy); > if (ret) > dev_warn(&rpdev->dev, "failed to nuke endpoints: %d\n", ret); > + mutex_unlock(&ctrldev->ctrl_lock); > > cdev_device_del(&ctrldev->cdev, &ctrldev->dev); > put_device(&ctrldev->dev);
