This is a note to let you know that I've just added the patch titled
net: qcom/emac: Fix use after free bug in emac_remove due to race condition
to the 4.19-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
net-qcom-emac-fix-use-after-free-bug-in-emac_remove-.patch
and it can be found in the queue-4.19 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 64212358a2a70e3b053daa9d56487a0364214e84
Author: Zheng Wang <zyytlz.wz@xxxxxxx>
Date: Sat Mar 18 16:05:26 2023 +0800
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: b9b17debc69d ("net: emac: emac gigabit ethernet controller driver")
Signed-off-by: Zheng Wang <zyytlz.wz@xxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/net/ethernet/qualcomm/emac/emac.c b/drivers/net/ethernet/qualcomm/emac/emac.c
index 76a9b37c8680f..3c764c28d5dbc 100644
--- a/drivers/net/ethernet/qualcomm/emac/emac.c
+++ b/drivers/net/ethernet/qualcomm/emac/emac.c
@@ -752,9 +752,15 @@ 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);
