Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S936642AbcJFIeU (ORCPT ); Thu, 6 Oct 2016 04:34:20 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:47032 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752181AbcJFIeQ (ORCPT ); Thu, 6 Oct 2016 04:34:16 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Sergei Miroshnichenko , Marc Kleine-Budde Subject: [PATCH 4.7 006/141] can: dev: fix deadlock reported after bus-off Date: Thu, 6 Oct 2016 10:27:22 +0200 Message-Id: <20161006074448.892099565@linuxfoundation.org> X-Mailer: git-send-email 2.10.0 In-Reply-To: <20161006074448.608056610@linuxfoundation.org> References: <20161006074448.608056610@linuxfoundation.org> User-Agent: quilt/0.64 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4194 Lines: 142 4.7-stable review patch. If anyone has any objections, please let me know. ------------------ From: Sergei Miroshnichenko commit 9abefcb1aaa58b9d5aa40a8bb12c87d02415e4c8 upstream. 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 Signed-off-by: Marc Kleine-Budde Signed-off-by: Greg Kroah-Hartman --- drivers/net/can/dev.c | 27 +++++++++++++++++---------- include/linux/can/dev.h | 3 ++- 2 files changed, 19 insertions(+), 11 deletions(-) --- a/drivers/net/can/dev.c +++ b/drivers/net/can/dev.c @@ -21,6 +21,7 @@ #include #include #include +#include #include #include #include @@ -471,9 +472,8 @@ 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; @@ -513,6 +513,14 @@ 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); @@ -526,8 +534,8 @@ int can_restart_now(struct net_device *d 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; } @@ -548,8 +556,8 @@ 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); @@ -658,6 +666,7 @@ struct net_device *alloc_candev(int size return NULL; priv = netdev_priv(dev); + priv->dev = dev; if (echo_skb_max) { priv->echo_skb_max = echo_skb_max; @@ -667,7 +676,7 @@ struct net_device *alloc_candev(int size priv->state = CAN_STATE_STOPPED; - init_timer(&priv->restart_timer); + INIT_DELAYED_WORK(&priv->restart_work, can_restart_work); return dev; } @@ -748,8 +757,6 @@ 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); @@ -764,7 +771,7 @@ 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); --- 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);