ravb: Fix use-after-free issue in ravb_tx_timeout_work()

The ravb_stop() should call cancel_work_sync(). Otherwise,
ravb_tx_timeout_work() is possible to use the freed priv after
ravb_remove() was called like below:

CPU0			CPU1
			ravb_tx_timeout()
ravb_remove()
unregister_netdev()
free_netdev(ndev)
// free priv
			ravb_tx_timeout_work()
			// use priv

unregister_netdev() will call .ndo_stop() so that ravb_stop() is
called. And, after phy_stop() is called, netif_carrier_off()
is also called. So that .ndo_tx_timeout() will not be called
after phy_stop().

Fixes: c156633f1353 ("Renesas Ethernet AVB driver proper")
Reported-by: Zheng Wang <[email protected]>
Closes: https://lore.kernel.org/netdev/[email protected]/
Signed-off-by: Yoshihiro Shimoda <[email protected]>
Reviewed-by: Sergey Shtylyov <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>

diff --git a/drivers/net/ethernet/renesas/ravb_main.c b/drivers/net/ethernet/renesas/ravb_main.c
index 9e2e801049cc89bbe6580c2083f363fff0345c81..0ef0b88b714590cef4ae0dbbc6dad2eee0579ee8 100644 (file)
--- a/drivers/net/ethernet/renesas/ravb_main.c
+++ b/drivers/net/ethernet/renesas/ravb_main.c
@@ -2167,6 +2167,8 @@ static int ravb_close(struct net_device *ndev)
                        of_phy_deregister_fixed_link(np);
        }
 
+       cancel_work_sync(&priv->work);
+
        if (info->multi_irqs) {
                free_irq(priv->tx_irqs[RAVB_NC], ndev);
                free_irq(priv->rx_irqs[RAVB_NC], ndev);