drivers/net/ethernet/qualcomm/emac/emac.c | 6 ++++++ 1 file changed, 6 insertions(+)
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 <email@example.com> --- v2: - 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); + 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); -- 2.25.1
Hello: This patch was applied to netdev/net.git (main) by David S. Miller <firstname.lastname@example.org>: On Sat, 18 Mar 2023 16:05:26 +0800 you wrote: > 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. > > [...] Here is the summary with links: - [net,v2] net: qcom/emac: Fix use after free bug in emac_remove due to race condition https://git.kernel.org/netdev/net/c/6b6bc5b8bd2d You are awesome, thank you! -- Deet-doot-dot, I am a bot. https://korg.docs.kernel.org/patchwork/pwbot.html
On Mon, 20 Mar 2023 09:20:17 +0000 email@example.com wrote: > Here is the summary with links: > - [net,v2] net: qcom/emac: Fix use after free bug in emac_remove due to race condition > https://git.kernel.org/netdev/net/c/6b6bc5b8bd2d Don't think this is correct FWIW, randomly shutting things down without holding any locks and before unregister_netdev() is called has got to be racy. Oh, eh.
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