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, Markus Pargmann , Marc Kleine-Budde Subject: [PATCH 3.11 11/36] can: c_can: Fix RX message handling, handle lost message before EOB Date: Tue, 26 Nov 2013 10:12:21 -0800 Message-Id: <20131126181027.347838651@linuxfoundation.org> In-Reply-To: <20131126181025.029404973@linuxfoundation.org> References: <20131126181025.029404973@linuxfoundation.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.11-stable review patch. If anyone has any objections, please let me know. ------------------ From: Markus Pargmann commit 5d0f801a2ccec3b1fdabc3392c8d99ed0413d216 upstream. If we handle end of block messages with higher priority than a lost message, we can run into an endless interrupt loop. This is reproducable with a am335x processor and "cansequence -r" at 1Mbit. As soon as we loose a packet we can't escape from an interrupt loop. This patch fixes the problem by handling lost packets before EOB packets. Signed-off-by: Markus Pargmann Signed-off-by: Marc Kleine-Budde Signed-off-by: Greg Kroah-Hartman --- drivers/net/can/c_can/c_can.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) --- a/drivers/net/can/c_can/c_can.c +++ b/drivers/net/can/c_can/c_can.c @@ -814,9 +814,6 @@ static int c_can_do_rx_poll(struct net_d msg_ctrl_save = priv->read_reg(priv, C_CAN_IFACE(MSGCTRL_REG, 0)); - if (msg_ctrl_save & IF_MCONT_EOB) - return num_rx_pkts; - if (msg_ctrl_save & IF_MCONT_MSGLST) { c_can_handle_lost_msg_obj(dev, 0, msg_obj); num_rx_pkts++; @@ -824,6 +821,9 @@ static int c_can_do_rx_poll(struct net_d continue; } + if (msg_ctrl_save & IF_MCONT_EOB) + return num_rx_pkts; + if (!(msg_ctrl_save & IF_MCONT_NEWDAT)) continue;