From: Vincent Mailhol mailhol.vincent@wanadoo.fr

In m_can_read_fifo(), if the second call to m_can_fifo_read() fails, the function jump to the out_fail label and returns without calling m_can_receive_skb(). This means that the skb previously allocated by alloc_can_skb() is not freed. In other terms, this is a memory leak.

This patch adds a goto label to destroy the skb if an error occurs.

Issue was found with GCC -fanalyzer, please follow the link below for details.

Fixes: e39381770ec9 ("can: m_can: Disable IRQs on FIFO bus errors") Link: https://lore.kernel.org/all/20211107050755.70655-1-mailhol.vincent@wanadoo.f... Cc: stable@vger.kernel.org Cc: Matt Kline matt@bitbashing.io Signed-off-by: Vincent Mailhol mailhol.vincent@wanadoo.fr Signed-off-by: Marc Kleine-Budde mkl@pengutronix.de --- drivers/net/can/m_can/m_can.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/net/can/m_can/m_can.c b/drivers/net/can/m_can/m_can.c index 91be87c4f4d3..e330b4c121bf 100644 --- a/drivers/net/can/m_can/m_can.c +++ b/drivers/net/can/m_can/m_can.c @@ -517,7 +517,7 @@ static int m_can_read_fifo(struct net_device *dev, u32 rxfs) err = m_can_fifo_read(cdev, fgi, M_CAN_FIFO_DATA, cf->data, DIV_ROUND_UP(cf->len, 4)); if (err) - goto out_fail; + goto out_free_skb; }

/* acknowledge rx fifo 0 */ @@ -532,6 +532,8 @@ static int m_can_read_fifo(struct net_device *dev, u32 rxfs)

return 0;

+out_free_skb: + kfree_skb(skb); out_fail: netdev_err(dev, "FIFO read returned %d\n", err); return err;