From: Marc Kleine-Budde Date: Wed, 5 May 2021 11:32:27 +0000 (+0200) Subject: can: m_can: m_can_tx_work_queue(): fix tx_skb race condition X-Git-Tag: v5.4.120~55 X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=51d3e462ea913a161c17e2eb8f658591d30a53bf;p=users%2Fdwmw2%2Flinux.git can: m_can: m_can_tx_work_queue(): fix tx_skb race condition [ 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 Signed-off-by: Marc Kleine-Budde Signed-off-by: Sasha Levin --- diff --git a/drivers/net/can/m_can/m_can.c b/drivers/net/can/m_can/m_can.c index b2224113987c7..de275ccb4fd0b 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,