mirror of
https://github.com/openwrt/openwrt.git
synced 2024-12-27 01:11:14 +00:00
129 lines
4.0 KiB
Diff
129 lines
4.0 KiB
Diff
From: Gregory CLEMENT <gregory.clement@free-electrons.com>
|
|
Date: Thu, 4 Feb 2016 22:09:29 +0100
|
|
Subject: [PATCH] net: mvneta: Fix race condition during stopping
|
|
|
|
When stopping the port, the CPU notifier are still there whereas the
|
|
mvneta_stop_dev function calls mvneta_percpu_disable() on each CPUs.
|
|
It was possible to have a new CPU coming at this point which could be
|
|
racy.
|
|
|
|
This patch adds a flag preventing executing the code notifier for a new
|
|
CPU when the port is stopping. It also uses the spinlock introduces
|
|
previously. To avoid the deadlock, the lock has been moved outside the
|
|
mvneta_percpu_elect function.
|
|
|
|
Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
|
|
Signed-off-by: David S. Miller <davem@davemloft.net>
|
|
---
|
|
|
|
--- a/drivers/net/ethernet/marvell/mvneta.c
|
|
+++ b/drivers/net/ethernet/marvell/mvneta.c
|
|
@@ -374,6 +374,7 @@ struct mvneta_port {
|
|
* ensuring that the configuration remains coherent.
|
|
*/
|
|
spinlock_t lock;
|
|
+ bool is_stopped;
|
|
|
|
/* Core clock */
|
|
struct clk *clk;
|
|
@@ -2853,16 +2854,14 @@ static void mvneta_percpu_disable(void *
|
|
disable_percpu_irq(pp->dev->irq);
|
|
}
|
|
|
|
+/* Electing a CPU must be done in an atomic way: it should be done
|
|
+ * after or before the removal/insertion of a CPU and this function is
|
|
+ * not reentrant.
|
|
+ */
|
|
static void mvneta_percpu_elect(struct mvneta_port *pp)
|
|
{
|
|
int elected_cpu = 0, max_cpu, cpu, i = 0;
|
|
|
|
- /* Electing a CPU must be done in an atomic way: it should be
|
|
- * done after or before the removal/insertion of a CPU and
|
|
- * this function is not reentrant.
|
|
- */
|
|
- spin_lock(&pp->lock);
|
|
-
|
|
/* Use the cpu associated to the rxq when it is online, in all
|
|
* the other cases, use the cpu 0 which can't be offline.
|
|
*/
|
|
@@ -2906,7 +2905,6 @@ static void mvneta_percpu_elect(struct m
|
|
i++;
|
|
|
|
}
|
|
- spin_unlock(&pp->lock);
|
|
};
|
|
|
|
static int mvneta_percpu_notifier(struct notifier_block *nfb,
|
|
@@ -2920,6 +2918,14 @@ static int mvneta_percpu_notifier(struct
|
|
switch (action) {
|
|
case CPU_ONLINE:
|
|
case CPU_ONLINE_FROZEN:
|
|
+ spin_lock(&pp->lock);
|
|
+ /* Configuring the driver for a new CPU while the
|
|
+ * driver is stopping is racy, so just avoid it.
|
|
+ */
|
|
+ if (pp->is_stopped) {
|
|
+ spin_unlock(&pp->lock);
|
|
+ break;
|
|
+ }
|
|
netif_tx_stop_all_queues(pp->dev);
|
|
|
|
/* We have to synchronise on tha napi of each CPU
|
|
@@ -2957,6 +2963,7 @@ static int mvneta_percpu_notifier(struct
|
|
MVNETA_CAUSE_LINK_CHANGE |
|
|
MVNETA_CAUSE_PSC_SYNC_CHANGE);
|
|
netif_tx_start_all_queues(pp->dev);
|
|
+ spin_unlock(&pp->lock);
|
|
break;
|
|
case CPU_DOWN_PREPARE:
|
|
case CPU_DOWN_PREPARE_FROZEN:
|
|
@@ -2981,7 +2988,9 @@ static int mvneta_percpu_notifier(struct
|
|
case CPU_DEAD:
|
|
case CPU_DEAD_FROZEN:
|
|
/* Check if a new CPU must be elected now this on is down */
|
|
+ spin_lock(&pp->lock);
|
|
mvneta_percpu_elect(pp);
|
|
+ spin_unlock(&pp->lock);
|
|
/* Unmask all ethernet port interrupts */
|
|
on_each_cpu(mvneta_percpu_unmask_interrupt, pp, true);
|
|
mvreg_write(pp, MVNETA_INTR_MISC_MASK,
|
|
@@ -3033,7 +3042,7 @@ static int mvneta_open(struct net_device
|
|
*/
|
|
on_each_cpu(mvneta_percpu_enable, pp, true);
|
|
|
|
-
|
|
+ pp->is_stopped = false;
|
|
/* Register a CPU notifier to handle the case where our CPU
|
|
* might be taken offline.
|
|
*/
|
|
@@ -3066,9 +3075,18 @@ static int mvneta_stop(struct net_device
|
|
{
|
|
struct mvneta_port *pp = netdev_priv(dev);
|
|
|
|
+ /* Inform that we are stopping so we don't want to setup the
|
|
+ * driver for new CPUs in the notifiers
|
|
+ */
|
|
+ spin_lock(&pp->lock);
|
|
+ pp->is_stopped = true;
|
|
mvneta_stop_dev(pp);
|
|
mvneta_mdio_remove(pp);
|
|
unregister_cpu_notifier(&pp->cpu_notifier);
|
|
+ /* Now that the notifier are unregistered, we can release le
|
|
+ * lock
|
|
+ */
|
|
+ spin_unlock(&pp->lock);
|
|
on_each_cpu(mvneta_percpu_disable, pp, true);
|
|
free_percpu_irq(dev->irq, pp->ports);
|
|
mvneta_cleanup_rxqs(pp);
|
|
@@ -3339,7 +3357,9 @@ static int mvneta_config_rss(struct mvn
|
|
mvreg_write(pp, MVNETA_PORT_CONFIG, val);
|
|
|
|
/* Update the elected CPU matching the new rxq_def */
|
|
+ spin_lock(&pp->lock);
|
|
mvneta_percpu_elect(pp);
|
|
+ spin_unlock(&pp->lock);
|
|
|
|
/* We have to synchronise on the napi of each CPU */
|
|
for_each_online_cpu(cpu) {
|