The copy_to_user() function returns the number of bytes which it wasn't able to copy but we want to return a negative error code. Fixes: 9d1a546c53b4 ("docs: Sample driver to demonstrate how to use Mediated device framework.") Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx> diff --git a/samples/vfio-mdev/mtty.c b/samples/vfio-mdev/mtty.c index 919c10d5b12e..d2656ff569c1 100644 --- a/samples/vfio-mdev/mtty.c +++ b/samples/vfio-mdev/mtty.c @@ -1180,7 +1180,10 @@ static long mtty_ioctl(struct mdev_device *mdev, unsigned int cmd, memcpy(&mdev_state->dev_info, &info, sizeof(info)); - return copy_to_user((void __user *)arg, &info, minsz); + if (copy_to_user((void __user *)arg, &info, minsz)) + return -EFAULT; + + return 0; } case VFIO_DEVICE_GET_REGION_INFO: { @@ -1201,7 +1204,10 @@ static long mtty_ioctl(struct mdev_device *mdev, unsigned int cmd, if (ret) return ret; - return copy_to_user((void __user *)arg, &info, minsz); + if (copy_to_user((void __user *)arg, &info, minsz)) + return -EFAULT; + + return 0; } case VFIO_DEVICE_GET_IRQ_INFO: @@ -1224,7 +1230,10 @@ static long mtty_ioctl(struct mdev_device *mdev, unsigned int cmd, if (info.count == -1) return -EINVAL; - return copy_to_user((void __user *)arg, &info, minsz); + if (copy_to_user((void __user *)arg, &info, minsz)) + return -EFAULT; + + return 0; } case VFIO_DEVICE_SET_IRQS: { -- To unsubscribe from this list: send the line "unsubscribe kernel-janitors" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html