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Date:   Sat, 18 Mar 2023 16:05:26 +0800
From:   Zheng Wang <>
        Zheng Wang <>
Subject: [PATCH net v2] net: qcom/emac: Fix use after free bug in emac_remove due to  race condition

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_remove         |
free_netdev         |
kfree(netdev);      |
                    |//use netdev
Fixes: b9b17debc69d ("net: emac: emac gigabit ethernet controller driver")
Signed-off-by: Zheng Wang <>
- cancel the work after unregister_netdev suggested by Jakub
 drivers/net/ethernet/qualcomm/emac/emac.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/net/ethernet/qualcomm/emac/emac.c b/drivers/net/ethernet/qualcomm/emac/emac.c
index 3115b2c12898..eaa50050aa0b 100644
--- a/drivers/net/ethernet/qualcomm/emac/emac.c
+++ b/drivers/net/ethernet/qualcomm/emac/emac.c
@@ -724,9 +724,15 @@ 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);
+	free_irq(adpt->irq.irq, &adpt->irq);
+	cancel_work_sync(&adpt->work_thread);

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