Subject: Re: [PATCH] net: stmmac: fix system hang when setting up standalone tag_8021q VLAN for DSA ports

From: Jakub Kicinski <[email-masked]>
Date: Fri, 7 Apr 2023 19:57:30 -0700

On Thu,  6 Apr 2023 18:04:37 +0800 louts wrote:
> The system hang because of dsa_tag_8021q_port_setup() callbcak
> stmmac_vlan_rx_add_vid().I found in stmmac_drv_probe() that
> cailing pm_runtime_put() disabled the clock when check the stmmac
> dirver.
> 
> First, when the kernel is compiled with CONFIG_PM=y,The stmmac's
> resume/suspend is active.
> 
> Secondly,stmmac as DSA master,the dsa_tag_8021q_port_setup() function
> will callback stmmac_vlan_rx_add_vid when DSA dirver starts. However,
> The system is hanged for the stmmac_vlan_rx_add_vid()  accesses its
> registers after stmmac's clock is closed.
> 
> I would suggest adding the pm_runtime_resume_and_get() to the
> stmmac_vlan_rx_add_vid().This guarantees that resuming clock output
> while in use.
> 
> Signed-off-by: louts <[email-masked]>

Is that your full name? If your name is not in the Latin alphabet
feel free to put it in brackets after the Latin version, e.g.:

Signed-off-by: John (якесь ім'я) <[email-masked]>

> @@ -6198,16 +6202,19 @@ static int stmmac_vlan_rx_add_vid(struct net_device *ndev, __be16 proto, u16 vid
>  	ret = stmmac_vlan_update(priv, is_double);
>  	if (ret) {
>  		clear_bit(vid, priv->active_vlans);
> -		return ret;
> +		goto update_vlan_error;
>  	}
>  
>  	if (priv->hw->num_vlan) {
>  		ret = stmmac_add_hw_vlan_rx_fltr(priv, ndev, priv->hw, proto, vid);
>  		if (ret)
> -			return ret;
> +			goto add_vlan_error;
>  	}
> +update_vlan_error:
> +add_vlan_error:

Name the labels after the target please.

err_pm_put:

> +	pm_runtime_put(priv->device);
>  
> -	return 0;
> +	return ret;