[PATCH net v3] net: ravb: Fix possible UAF bug in ravb_remove

[Zheng Wang]

In ravb_probe, priv->work was bound with ravb_tx_timeout_work.
If timeout occurs, it will start the work. And if we call
ravb_remove without finishing the work, there may be a
use-after-free bug on ndev.

Fix it by finishing the job before cleanup in ravb_remove.

Fixes: c156633f1353 ("Renesas Ethernet AVB driver proper")
Signed-off-by: Zheng Wang <zyytlz.wz@xxxxxxx>
Reviewed-by: Sergey Shtylyov <s.shtylyov@xxxxxx>
---
v3:
- fix typo in commit message
v2:
- stop dev_watchdog so that handle no more timeout work suggested by Yunsheng Lin,
add an empty line to make code clear suggested by Sergey Shtylyov
---
 drivers/net/ethernet/renesas/ravb_main.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/net/ethernet/renesas/ravb_main.c b/drivers/net/ethernet/renesas/ravb_main.c
index 0f54849a3823..eb63ea788e19 100644
--- a/drivers/net/ethernet/renesas/ravb_main.c
+++ b/drivers/net/ethernet/renesas/ravb_main.c
@@ -2892,6 +2892,10 @@ static int ravb_remove(struct platform_device *pdev)
 	struct ravb_private *priv = netdev_priv(ndev);
 	const struct ravb_hw_info *info = priv->info;
 
+	netif_carrier_off(ndev);
+	netif_tx_disable(ndev);
+	cancel_work_sync(&priv->work);
+	
 	/* Stop PTP Clock driver */
 	if (info->ccc_gac)
 		ravb_ptp_stop(ndev);
-- 
2.25.1