From: Marc Kleine-Budde mkl@pengutronix.de
[ Upstream commit e04b2cfe61072c7966e1a5fb73dd1feb30c206ed ]
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: f524f829b75a ("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 Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/net/can/m_can/m_can.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/net/can/m_can/m_can.c b/drivers/net/can/m_can/m_can.c index b2224113987c..de275ccb4fd0 100644 --- a/drivers/net/can/m_can/m_can.c +++ b/drivers/net/can/m_can/m_can.c @@ -1418,6 +1418,8 @@ 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) { @@ -1534,7 +1536,6 @@ 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,