From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Johan Hovold , Sasha Levin Subject: [PATCH 4.14 060/159] serdev: fix receive_buf return value when no callback Date: Fri, 23 Feb 2018 19:26:08 +0100 Message-Id: <20180223170750.850913741@linuxfoundation.org> In-Reply-To: <20180223170743.086611315@linuxfoundation.org> References: <20180223170743.086611315@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: 4.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Johan Hovold [ Upstream commit fd00cf81a9a84776ba58e56bd042c726dcf75cf3 ] The receive_buf callback is supposed to return the number of bytes processed and should specifically not return a negative errno. Due to missing sanity checks in the serdev tty-port controller, a driver not providing a receive_buf callback could cause the flush_to_ldisc() worker to spin in a tight loop when the tty buffer pointers are incremented with -EINVAL (-22). The missing sanity checks have now been added to the tty-port controller, but let's fix up the serdev-controller helper as well. Signed-off-by: Johan Hovold Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- include/linux/serdev.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/include/linux/serdev.h +++ b/include/linux/serdev.h @@ -184,7 +184,7 @@ static inline int serdev_controller_rece struct serdev_device *serdev = ctrl->serdev; if (!serdev || !serdev->ops->receive_buf) - return -EINVAL; + return 0; return serdev->ops->receive_buf(serdev, data, count); }