From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marc Kleine-Budde Subject: [PATCH 2/4] can: c_can: don't call pm_runtime_get_sync() from interrupt context Date: Wed, 27 Nov 2013 22:11:33 +0100 Message-ID: <1385586695-11134-3-git-send-email-mkl@pengutronix.de> References: <1385586695-11134-1-git-send-email-mkl@pengutronix.de> Cc: davem@davemloft.net, linux-can@vger.kernel.org, kernel@pengutronix.de, Marc Kleine-Budde , Andrew Glen , linux-stable To: netdev@vger.kernel.org Return-path: Received: from metis.ext.pengutronix.de ([92.198.50.35]:49155 "EHLO metis.ext.pengutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757681Ab3K0VLv (ORCPT ); Wed, 27 Nov 2013 16:11:51 -0500 In-Reply-To: <1385586695-11134-1-git-send-email-mkl@pengutronix.de> Sender: netdev-owner@vger.kernel.org List-ID: The c_can driver contians a callpath (c_can_poll -> c_can_state_change -> c_can_get_berr_counter) which may call pm_runtime_get_sync() from the IRQ handler, which is not allowed and results in "BUG: scheduling while atomic". This problem is fixed by introducing __c_can_get_berr_counter, which will not call pm_runtime_get_sync(). Reported-by: Andrew Glen Tested-by: Andrew Glen Signed-off-by: Andrew Glen Cc: linux-stable Signed-off-by: Marc Kleine-Budde --- drivers/net/can/c_can/c_can.c | 21 +++++++++++++++------ 1 file changed, 15 insertions(+), 6 deletions(-) diff --git a/drivers/net/can/c_can/c_can.c b/drivers/net/can/c_can/c_can.c index e3fc07c..e59c42b 100644 --- a/drivers/net/can/c_can/c_can.c +++ b/drivers/net/can/c_can/c_can.c @@ -712,22 +712,31 @@ static int c_can_set_mode(struct net_device *dev, enum can_mode mode) return 0; } -static int c_can_get_berr_counter(const struct net_device *dev, - struct can_berr_counter *bec) +static int __c_can_get_berr_counter(const struct net_device *dev, + struct can_berr_counter *bec) { unsigned int reg_err_counter; struct c_can_priv *priv = netdev_priv(dev); - c_can_pm_runtime_get_sync(priv); - reg_err_counter = priv->read_reg(priv, C_CAN_ERR_CNT_REG); bec->rxerr = (reg_err_counter & ERR_CNT_REC_MASK) >> ERR_CNT_REC_SHIFT; bec->txerr = reg_err_counter & ERR_CNT_TEC_MASK; + return 0; +} + +static int c_can_get_berr_counter(const struct net_device *dev, + struct can_berr_counter *bec) +{ + struct c_can_priv *priv = netdev_priv(dev); + int err; + + c_can_pm_runtime_get_sync(priv); + err = __c_can_get_berr_counter(dev, bec); c_can_pm_runtime_put_sync(priv); - return 0; + return err; } /* @@ -872,7 +881,7 @@ static int c_can_handle_state_change(struct net_device *dev, if (unlikely(!skb)) return 0; - c_can_get_berr_counter(dev, &bec); + __c_can_get_berr_counter(dev, &bec); reg_err_counter = priv->read_reg(priv, C_CAN_ERR_CNT_REG); rx_err_passive = (reg_err_counter & ERR_CNT_RP_MASK) >> ERR_CNT_RP_SHIFT; -- 1.8.5.rc0