From: Sergei Miroshnichenko <sergei...@emcraft.com> 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 <sergei...@emcraft.com> Cc: linux-stable <sta...@vger.kernel.org> Signed-off-by: Marc Kleine-Budde <m...@pengutronix.de> --- drivers/net/can/dev.c | 27 +++++++++++++++++---------- include/linux/can/dev.h | 3 ++- 2 files changed, 19 insertions(+), 11 deletions(-) diff --git a/drivers/net/can/dev.c b/drivers/net/can/dev.c index e21f7cc5ae4d..8d6208c0b400 100644 --- a/drivers/net/can/dev.c +++ b/drivers/net/can/dev.c @@ -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 @@ restart: 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); diff --git a/include/linux/can/dev.h b/include/linux/can/dev.h index 5261751f6bd4..5f5270941ba0 100644 --- a/include/linux/can/dev.h +++ b/include/linux/can/dev.h @@ -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); -- 2.9.3
