Subject: Re: [PATCH net-next 01/18] net/smc: decouple ism_dev from SMC-D device dump

From: Simon Horman <[email-masked]>
Date: Thu, 21 Sep 2023 21:41:53 +0100

On Tue, Sep 19, 2023 at 10:41:45PM +0800, Wen Gu wrote:
> This patch helps to decouple ISM device from SMC-D device, allowing
> different underlying device forms, such as virtual ISM devices.
> 
> Signed-off-by: Wen Gu <[email-masked]>
> ---
>  net/smc/smc_ism.c | 8 +++++---
>  1 file changed, 5 insertions(+), 3 deletions(-)
> 
> diff --git a/net/smc/smc_ism.c b/net/smc/smc_ism.c
> index fbee249..0045fee 100644
> --- a/net/smc/smc_ism.c
> +++ b/net/smc/smc_ism.c
> @@ -230,12 +230,11 @@ static int smc_nl_handle_smcd_dev(struct smcd_dev *smcd,
>  	char smc_pnet[SMC_MAX_PNETID_LEN + 1];
>  	struct smc_pci_dev smc_pci_dev;
>  	struct nlattr *port_attrs;
> +	struct device *priv_dev;
>  	struct nlattr *attrs;
> -	struct ism_dev *ism;
>  	int use_cnt = 0;
>  	void *nlh;
>  
> -	ism = smcd->priv;
>  	nlh = genlmsg_put(skb, NETLINK_CB(cb->skb).portid, cb->nlh->nlmsg_seq,
>  			  &smc_gen_nl_family, NLM_F_MULTI,
>  			  SMC_NETLINK_GET_DEV_SMCD);
> @@ -250,7 +249,10 @@ static int smc_nl_handle_smcd_dev(struct smcd_dev *smcd,
>  	if (nla_put_u8(skb, SMC_NLA_DEV_IS_CRIT, use_cnt > 0))
>  		goto errattr;
>  	memset(&smc_pci_dev, 0, sizeof(smc_pci_dev));

Hi Wen Gu,

priv_dev is uninitialised here.

> -	smc_set_pci_values(to_pci_dev(ism->dev.parent), &smc_pci_dev);
> +	if (smcd->ops->get_dev)
> +		priv_dev = smcd->ops->get_dev(smcd);

It is conditionally initialised here.

> +	if (priv_dev->parent)

But unconditionally dereferenced here.

As flagged by clang-16 W=1, and Smatch

> +		smc_set_pci_values(to_pci_dev(priv_dev->parent), &smc_pci_dev);
>  	if (nla_put_u32(skb, SMC_NLA_DEV_PCI_FID, smc_pci_dev.pci_fid))
>  		goto errattr;
>  	if (nla_put_u16(skb, SMC_NLA_DEV_PCI_CHID, smc_pci_dev.pci_pchid))
> -- 
> 1.8.3.1
> 
>