* [PATCH net] net: qcom/emac: Fix use after free bug in emac_remove due to race condition
@ 2023-03-10 10:57 Zheng Wang
2023-03-14 0:00 ` Jakub Kicinski
0 siblings, 1 reply; 3+ messages in thread
From: Zheng Wang @ 2023-03-10 10:57 UTC (permalink / raw)
To: timur
Cc: davem, edumazet, kuba, pabeni, netdev, linux-kernel,
hackerzheng666, 1395428693sheep, alex000young, Zheng Wang
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@163.com>
---
drivers/net/ethernet/qualcomm/emac/emac.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/net/ethernet/qualcomm/emac/emac.c b/drivers/net/ethernet/qualcomm/emac/emac.c
index 3115b2c12898..ddc328f7b96a 100644
--- a/drivers/net/ethernet/qualcomm/emac/emac.c
+++ b/drivers/net/ethernet/qualcomm/emac/emac.c
@@ -724,6 +724,9 @@ 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);
+ cancel_work_sync(&adpt->work_thread);
unregister_netdev(netdev);
netif_napi_del(&adpt->rx_q.napi);
--
2.25.1
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH net] net: qcom/emac: Fix use after free bug in emac_remove due to race condition
2023-03-10 10:57 [PATCH net] net: qcom/emac: Fix use after free bug in emac_remove due to race condition Zheng Wang
@ 2023-03-14 0:00 ` Jakub Kicinski
2023-03-14 2:11 ` Zheng Hacker
0 siblings, 1 reply; 3+ messages in thread
From: Jakub Kicinski @ 2023-03-14 0:00 UTC (permalink / raw)
To: Zheng Wang
Cc: timur, davem, edumazet, pabeni, netdev, linux-kernel,
hackerzheng666, 1395428693sheep, alex000young
On Fri, 10 Mar 2023 18:57:34 +0800 Zheng Wang wrote:
> + netif_carrier_off(netdev);
> + netif_tx_disable(netdev);
> + cancel_work_sync(&adpt->work_thread);
> unregister_netdev(netdev);
> netif_napi_del(&adpt->rx_q.napi);
same problem as in the natsemi driver
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH net] net: qcom/emac: Fix use after free bug in emac_remove due to race condition
2023-03-14 0:00 ` Jakub Kicinski
@ 2023-03-14 2:11 ` Zheng Hacker
0 siblings, 0 replies; 3+ messages in thread
From: Zheng Hacker @ 2023-03-14 2:11 UTC (permalink / raw)
To: Jakub Kicinski
Cc: Zheng Wang, timur, davem, edumazet, pabeni, netdev, linux-kernel,
1395428693sheep, alex000young
Jakub Kicinski <kuba@kernel.org> 于2023年3月14日周二 08:00写道:
>
> On Fri, 10 Mar 2023 18:57:34 +0800 Zheng Wang wrote:
> > + netif_carrier_off(netdev);
> > + netif_tx_disable(netdev);
> > + cancel_work_sync(&adpt->work_thread);
> > unregister_netdev(netdev);
> > netif_napi_del(&adpt->rx_q.napi);
>
> same problem as in the natsemi driver
Hi Jakub,
Thanks for your reply. Here we schedule the work when handling IRQ
request, So I think we should add free_irq after netif_napi_del and move
the cancel_work_sync after that like:
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);
Apprecaite for your advice about the fix.
Best regards,
Zheng
^ permalink raw reply [flat|nested] 3+ messages in thread
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2023-03-10 10:57 [PATCH net] net: qcom/emac: Fix use after free bug in emac_remove due to race condition Zheng Wang
2023-03-14 0:00 ` Jakub Kicinski
2023-03-14 2:11 ` Zheng Hacker
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