can: m_can: m_can_tx_work_queue(): fix tx_skb race condition

The m_can_start_xmit() function checks if the cdev->tx_skb is NULL and
returns with NETDEV_TX_BUSY in case tx_sbk is not NULL.

There is a race condition in the m_can_tx_work_queue(), where first
the skb is send to the driver and then the case tx_sbk is set to NULL.
A TX complete IRQ might come in between and wake the queue, which
results in tx_skb not being cleared yet.

Fixes: f524f829b7 ("can: m_can: Create a m_can platform framework")
Tested-by: Torin Cooper-Bennun <torin@maxiluxsystems.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
This commit is contained in:
Marc Kleine-Budde 2021-05-05 13:32:27 +02:00
parent 03c427147b
commit e04b2cfe61

View File

@ -1562,6 +1562,8 @@ static netdev_tx_t m_can_tx_handler(struct m_can_classdev *cdev)
int i;
int putidx;
cdev->tx_skb = NULL;
/* Generate ID field for TX buffer Element */
/* Common to all supported M_CAN versions */
if (cf->can_id & CAN_EFF_FLAG) {
@ -1678,7 +1680,6 @@ static void m_can_tx_work_queue(struct work_struct *ws)
tx_work);
m_can_tx_handler(cdev);
cdev->tx_skb = NULL;
}
static netdev_tx_t m_can_start_xmit(struct sk_buff *skb,