Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933146AbcJQIKt (ORCPT ); Mon, 17 Oct 2016 04:10:49 -0400 Received: from mx2.suse.de ([195.135.220.15]:47123 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757798AbcJQHze (ORCPT ); Mon, 17 Oct 2016 03:55:34 -0400 X-Amavis-Alert: BAD HEADER SECTION, Duplicate header field: "References" From: Jiri Slaby To: stable@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Sergei Miroshnichenko , Marc Kleine-Budde , Jiri Slaby Subject: [PATCH 3.12 42/84] can: dev: fix deadlock reported after bus-off Date: Mon, 17 Oct 2016 09:51:29 +0200 Message-Id: <1ab93b13fe17bbab243148d6b77ed672bd558c53.1476690493.git.jslaby@suse.cz> X-Mailer: git-send-email 2.10.1 In-Reply-To: <2d291fde5f706ac081e8cfc0ebe7e31dd534dfe7.1476690493.git.jslaby@suse.cz> References: <2d291fde5f706ac081e8cfc0ebe7e31dd534dfe7.1476690493.git.jslaby@suse.cz> In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4404 Lines: 146 From: Sergei Miroshnichenko 3.12-stable review patch. If anyone has any objections, please let me know. =============== 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: Jiri Slaby --- 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 464e5f66b66d..284d751ea97f 100644 --- a/drivers/net/can/dev.c +++ b/drivers/net/can/dev.c @@ -22,6 +22,7 @@ #include #include #include +#include #include #include #include @@ -394,9 +395,8 @@ 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; @@ -436,6 +436,14 @@ 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); @@ -449,8 +457,8 @@ 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; } @@ -472,8 +480,8 @@ void can_bus_off(struct net_device *dev) priv->can_stats.bus_off++; 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); @@ -556,6 +564,7 @@ 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; @@ -565,7 +574,7 @@ 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; } @@ -599,8 +608,6 @@ 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); @@ -615,7 +622,7 @@ 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 fb0ab651a041..fb9fbe2f63e7 100644 --- a/include/linux/can/dev.h +++ b/include/linux/can/dev.h @@ -31,6 +31,7 @@ enum can_mode { * CAN common private data */ struct can_priv { + struct net_device *dev; struct can_device_stats can_stats; struct can_bittiming bittiming; @@ -42,7 +43,7 @@ struct can_priv { u32 ctrlmode_supported; int restart_ms; - struct timer_list restart_timer; + struct delayed_work restart_work; int (*do_set_bittiming)(struct net_device *dev); int (*do_set_mode)(struct net_device *dev, enum can_mode mode); -- 2.10.1