From e04b2cfe61072c7966e1a5fb73dd1feb30c206ed Mon Sep 17 00:00:00 2001 From: Marc Kleine-Budde Date: Wed, 5 May 2021 13:32:27 +0200 Subject: [PATCH] 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: f524f829b75a ("can: m_can: Create a m_can platform framework") Tested-by: Torin Cooper-Bennun Signed-off-by: Marc Kleine-Budde --- 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 34073cd..3cf6de2 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, -- 2.7.4