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Commit 0e5c7d00 authored by Zheng Wang's avatar Zheng Wang Committed by Greg Kroah-Hartman
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net: qcom/emac: Fix use after free bug in emac_remove due to race condition 



[ Upstream commit 6b6bc5b8bd2d4ca9e1efa9ae0f98a0b0687ace75 ]

In emac_probe, &adpt->work_thread is bound with
emac_work_thread. Then it will be started by timeout
handler emac_tx_timeout or a IRQ handler emac_isr.

If we remove the driver which will call emac_remove
  to make cleanup, there may be a unfinished work.

The possible sequence is as follows:

Fix it by finishing the work before cleanup in the emac_remove
and disable timeout response.

CPU0                  CPU1

                    |emac_work_thread
emac_remove         |
free_netdev         |
kfree(netdev);      |
                    |emac_reinit_locked
                    |emac_mac_down
                    |//use netdev
Fixes: b9b17deb ("net: emac: emac gigabit ethernet controller driver")
Signed-off-by: default avatarZheng Wang <zyytlz.wz@163.com>

Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent a07ec453

drivers/net/ethernet/qualcomm/emac/emac.c

+6 −0
Original line number Diff line number Diff line
@@ -738,9 +738,15 @@ static int emac_remove(struct platform_device *pdev) 
	struct net_device *netdev = dev_get_drvdata(&pdev->dev);

	struct emac_adapter *adpt = netdev_priv(netdev);



	netif_carrier_off(netdev);

	netif_tx_disable(netdev);



	unregister_netdev(netdev);

	netif_napi_del(&adpt->rx_q.napi);



	free_irq(adpt->irq.irq, &adpt->irq);

	cancel_work_sync(&adpt->work_thread);



	emac_clks_teardown(adpt);



	put_device(&adpt->phydev->mdio.dev);