From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752555AbdHVSi2 (ORCPT ); Tue, 22 Aug 2017 14:38:28 -0400 Received: from laurent.telenet-ops.be ([195.130.137.89]:46974 "EHLO laurent.telenet-ops.be" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752362AbdHVShi (ORCPT ); Tue, 22 Aug 2017 14:37:38 -0400 From: Geert Uytterhoeven To: "David S . Miller" , Steve Glendinning , Andrew Lunn , Florian Fainelli Cc: Lukas Wunner , "Rafael J . Wysocki" , netdev@vger.kernel.org, linux-pm@vger.kernel.org, linux-renesas-soc@vger.kernel.org, linux-kernel@vger.kernel.org, Geert Uytterhoeven Subject: [PATCH 2/2] net: smsc911x: Quiten netif during suspend Date: Tue, 22 Aug 2017 20:37:26 +0200 Message-Id: <1503427046-17618-3-git-send-email-geert+renesas@glider.be> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1503427046-17618-1-git-send-email-geert+renesas@glider.be> References: <1503427046-17618-1-git-send-email-geert+renesas@glider.be> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org If the network interface is kept running during suspend, the net core may call net_device_ops.ndo_start_xmit() while the Ethernet device is still suspended, which may lead to a system crash. E.g. on sh73a0/kzm9g and r8a73a4/ape6evm, the external Ethernet chip is driven by a PM controlled clock. If the Ethernet registers are accessed while the clock is not running, the system will crash with an imprecise external abort. As this is a race condition with a small time window, it is not so easy to trigger at will. Using pm_test may increase your chances: # echo 0 > /sys/module/printk/parameters/console_suspend # echo platform > /sys/power/pm_test # echo mem > /sys/power/state To fix this, make sure the network interface is quitened during suspend. Signed-off-by: Geert Uytterhoeven --- No stacktrace is provided, as the imprecise external abort is usually reported from an innocent looking and unrelated function like __loop_delay(), cpu_idle_poll(), or arch_timer_read_counter_long(). --- drivers/net/ethernet/smsc/smsc911x.c | 15 ++++++++++++++- 1 file changed, 14 insertions(+), 1 deletion(-) diff --git a/drivers/net/ethernet/smsc/smsc911x.c b/drivers/net/ethernet/smsc/smsc911x.c index 0b6a39b003a4e188..012fb66eed8dd618 100644 --- a/drivers/net/ethernet/smsc/smsc911x.c +++ b/drivers/net/ethernet/smsc/smsc911x.c @@ -2595,6 +2595,11 @@ static int smsc911x_suspend(struct device *dev) struct net_device *ndev = dev_get_drvdata(dev); struct smsc911x_data *pdata = netdev_priv(ndev); + if (netif_running(ndev)) { + netif_stop_queue(ndev); + netif_device_detach(ndev); + } + /* enable wake on LAN, energy detection and the external PME * signal. */ smsc911x_reg_write(pdata, PMT_CTRL, @@ -2628,7 +2633,15 @@ static int smsc911x_resume(struct device *dev) while (!(smsc911x_reg_read(pdata, PMT_CTRL) & PMT_CTRL_READY_) && --to) udelay(1000); - return (to == 0) ? -EIO : 0; + if (to == 0) + return -EIO; + + if (netif_running(ndev)) { + netif_device_attach(ndev); + netif_start_queue(ndev); + } + + return 0; } static const struct dev_pm_ops smsc911x_pm_ops = { -- 2.7.4