Subject: Re: [PATCH 3/8] staging: wfx: standardize the error when vif does not exist

From: Kalle Valo <[email-masked]>
Date: Fri, 09 Oct 2020 21:52:47 +0300

Jerome Pouiller <[email-masked]> writes:

> From: Jérôme Pouiller <[email-masked]>
>
> Smatch complains:
>
>    drivers/staging/wfx/hif_rx.c:177 hif_scan_complete_indication() warn: potential NULL parameter dereference 'wvif'
>    drivers/staging/wfx/data_tx.c:576 wfx_flush() warn: potential NULL parameter dereference 'wvif'
>
> Indeed, if the vif id returned by the device does not exist anymore,
> wdev_to_wvif() could return NULL.
>
> In add, the error is not handled uniformly in the code, sometime a
> WARN() is displayed but code continue, sometime a dev_warn() is
> displayed, sometime it is just not tested, ...
>
> This patch standardize that.
>
> Reported-by: Dan Carpenter <[email-masked]>
> Signed-off-by: Jérôme Pouiller <[email-masked]>
> ---
>  drivers/staging/wfx/data_tx.c |  5 ++++-
>  drivers/staging/wfx/hif_rx.c  | 34 ++++++++++++++++++++++++----------
>  drivers/staging/wfx/sta.c     |  4 ++++
>  3 files changed, 32 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/staging/wfx/data_tx.c b/drivers/staging/wfx/data_tx.c
> index b4d5dd3d2d23..8db0be08daf8 100644
> --- a/drivers/staging/wfx/data_tx.c
> +++ b/drivers/staging/wfx/data_tx.c
> @@ -431,7 +431,10 @@ static void wfx_skb_dtor(struct wfx_vif *wvif, struct sk_buff *skb)
>  			      sizeof(struct hif_req_tx) +
>  			      req->fc_offset;
>  
> -	WARN_ON(!wvif);
> +	if (!wvif) {
> +		pr_warn("%s: vif associated with the skb does not exist anymore\n", __func__);
> +		return;
> +	}

I'm not really a fan of using function names in warning or error
messages as it clutters the log. In debug messages I think they are ok.

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