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@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx>
---
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 34073cd077e4..3cf6de21d19c 100644
--- a/drivers/net/can/m_can/m_can.c
+++ b/drivers/net/can/m_can/m_can.c
@@ -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,
--
2.30.2
