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Commit e35d46ad authored by Marc Kleine-Budde's avatar Marc Kleine-Budde
Browse files

can: c_can: don't call pm_runtime_get_sync() from interrupt context 



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: default avatarAndrew Glen <AGlen@bepmarine.com>
Tested-by: default avatarAndrew Glen <AGlen@bepmarine.com>
Signed-off-by: default avatarAndrew Glen <AGlen@bepmarine.com>
Cc: linux-stable <stable@vger.kernel.org>
Signed-off-by: default avatarMarc Kleine-Budde <mkl@pengutronix.de>
parent 2fea6cd3

drivers/net/can/c_can/c_can.c

+15 −6
Original line number Diff line number Diff line
@@ -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,

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;