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can: dev: fix deadlock reported after bus-off 

A timer was used to restart after the bus-off state, leading to a
relatively large can_restart() executed in an interrupt context,
which in turn sets up pinctrl. When this happens during system boot,
there is a high probability of grabbing the pinctrl_list_mutex,
which is locked already by the probe() of other device, making the
kernel suspect a deadlock condition [1].

To resolve this issue, the restart_timer is replaced by a delayed
work.

[1] https://github.com/victronenergy/venus/issues/24

Signed-off-by: Sergei Miroshnichenko <sergeimir@emcraft.com>
Cc: linux-stable <stable@vger.kernel.org>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
This commit is contained in:
Sergei Miroshnichenko 2016-09-07 16:51:12 +03:00 committed by Marc Kleine-Budde
parent 7e32b44361
commit 9abefcb1aa
2 changed files with 19 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

27
drivers/net/can/dev.c
View File

@ -21,6 +21,7 @@
#include <linux/slab.h>
#include <linux/netdevice.h>
#include <linux/if_arp.h>
#include <linux/workqueue.h>
#include <linux/can.h>
#include <linux/can/dev.h>
#include <linux/can/skb.h>
@ -501,9 +502,8 @@ EXPORT_SYMBOL_GPL(can_free_echo_skb);
/*
* CAN device restart for bus-off recovery
*/
static void can_restart(unsigned long data)
static void can_restart(struct net_device *dev)
{
struct net_device *dev = (struct net_device *)data;
struct can_priv *priv = netdev_priv(dev);
struct net_device_stats *stats = &dev->stats;
struct sk_buff *skb;
@ -543,6 +543,14 @@ static void can_restart(unsigned long data)
netdev_err(dev, "Error %d during restart", err);
}
static void can_restart_work(struct work_struct *work)
{
struct delayed_work *dwork = to_delayed_work(work);
struct can_priv *priv = container_of(dwork, struct can_priv, restart_work);
can_restart(priv->dev);
}
int can_restart_now(struct net_device *dev)
{
struct can_priv *priv = netdev_priv(dev);
@ -556,8 +564,8 @@ int can_restart_now(struct net_device *dev)
if (priv->state != CAN_STATE_BUS_OFF)
return -EBUSY;
/* Runs as soon as possible in the timer context */
mod_timer(&priv->restart_timer, jiffies);
cancel_delayed_work_sync(&priv->restart_work);
can_restart(dev);
return 0;
}
@ -578,8 +586,8 @@ void can_bus_off(struct net_device *dev)
netif_carrier_off(dev);
if (priv->restart_ms)
mod_timer(&priv->restart_timer,
jiffies + (priv->restart_ms * HZ) / 1000);
schedule_delayed_work(&priv->restart_work,
msecs_to_jiffies(priv->restart_ms));
}
EXPORT_SYMBOL_GPL(can_bus_off);
@ -688,6 +696,7 @@ struct net_device *alloc_candev(int sizeof_priv, unsigned int echo_skb_max)
return NULL;
priv = netdev_priv(dev);
priv->dev = dev;
if (echo_skb_max) {
priv->echo_skb_max = echo_skb_max;
@ -697,7 +706,7 @@ struct net_device *alloc_candev(int sizeof_priv, unsigned int echo_skb_max)
priv->state = CAN_STATE_STOPPED;
init_timer(&priv->restart_timer);
INIT_DELAYED_WORK(&priv->restart_work, can_restart_work);
return dev;
}
@ -778,8 +787,6 @@ int open_candev(struct net_device *dev)
if (!netif_carrier_ok(dev))
netif_carrier_on(dev);
setup_timer(&priv->restart_timer, can_restart, (unsigned long)dev);
return 0;
}
EXPORT_SYMBOL_GPL(open_candev);
@ -794,7 +801,7 @@ void close_candev(struct net_device *dev)
{
struct can_priv *priv = netdev_priv(dev);
del_timer_sync(&priv->restart_timer);
cancel_delayed_work_sync(&priv->restart_work);
can_flush_echo_skb(dev);
}
EXPORT_SYMBOL_GPL(close_candev);

3
include/linux/can/dev.h
View File

@ -32,6 +32,7 @@ enum can_mode {
* CAN common private data
*/
struct can_priv {
struct net_device *dev;
struct can_device_stats can_stats;
struct can_bittiming bittiming, data_bittiming;
@ -47,7 +48,7 @@ struct can_priv {
u32 ctrlmode_static; /* static enabled options for driver/hardware */
int restart_ms;
struct timer_list restart_timer;
struct delayed_work restart_work;
int (*do_set_bittiming)(struct net_device *dev);
int (*do_set_data_bittiming)(struct net_device *dev);