Re: [PATCH net] gve: use gve_schedule_reset() on AdminQ flow rule timeout

On 8/6/26 10:51, Rénich Bon Ćirić wrote:
> When an AdminQ command to configure a flow rule times out in
> gve_adminq_configure_flow_rule(), the driver currently calls
> gve_reset(priv, true) synchronously.
> 
> When flow rule configuration is invoked under netlink or ethtool
> callbacks, gve_reset() attempts to acquire rtnl_lock while already
> executing within an inner driver lock context. This violates the driver's
> lock hierarchy and causes an AB-BA circular lock inversion deadlock.
> 
> Resolve this lock inversion by replacing synchronous gve_reset() with
> gve_schedule_reset(). This defers reset execution safely to
> gve_service_task out-of-band under the proper lock ordering.
> 
> Fixes: 8ffade77b633 ("gve: Flow steering trigger reset only for timeout error")

this is not the commit that introduced the bug

initial implementation was in commit 57718b60df9b ("gve: Add flow 
steering adminq commands"), so this could be used as "wrong code intro",
but likely it was the addition of netdev_lock() around ethtool call,
that exposed the issue, and should be the actual Fixes tag

> Link: https://github.com/GoogleCloudPlatform/compute-virtual-ethernet-linux/issues/93
> Signed-off-by: Rénich Bon Ćirić <[email protected]>
> ---
>   drivers/net/ethernet/google/gve/gve_adminq.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/net/ethernet/google/gve/gve_adminq.c b/drivers/net/ethernet/google/gve/gve_adminq.c
> index 08587bf12345..2037b1767890 100644
> --- a/drivers/net/ethernet/google/gve/gve_adminq.c
> +++ b/drivers/net/ethernet/google/gve/gve_adminq.c
> @@ -1322,7 +1322,7 @@ gve_adminq_configure_flow_rule(struct gve_priv *priv,
>   
>   	if (err == -ETIME) {
>   		dev_err(&priv->pdev->dev, "Timeout to configure the flow rule, trigger reset");
> -		gve_reset(priv, true);
> +		gve_schedule_reset(priv);
>   	} else if (!err) {
>   		priv->flow_rules_cache.rules_cache_synced = false;
>   	}

code looks good, after updating Fixes tag, feel free to add my:
Reviewed-by: Przemek Kitszel <[email protected]>