From 2aa70f864955bf02362e3fb3008e4208d7a17a98 Mon Sep 17 00:00:00 2001
From: Geert Uytterhoeven <geert+renesas@glider.be>
Date: Wed, 13 Sep 2017 19:42:05 +0200
Subject: [PATCH] net: smsc911x: Quieten netif during suspend
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 quietened during
suspend.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
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 0b6a39b003a4..012fb66eed8d 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 = {