[Xenial][PATCH 1/2] net/wireless: do not dereference invalid pointer

[Colin Ian King]

On 24/08/17 08:30, Wen-chien Jesse Sung wrote:
> BugLink: https://launchpad.net/bugs/1712746
> 
> The wiphy may be NULL sometimes. Do not dereference when it's NULL.
> 
> Signed-off-by: Wen-chien Jesse Sung <jesse.sung at canonical.com>
> ---
>  net/wireless/util.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/net/wireless/util.c b/net/wireless/util.c
> index baf7218..e358511 100644
> --- a/net/wireless/util.c
> +++ b/net/wireless/util.c
> @@ -121,7 +121,7 @@ struct ieee80211_channel *__ieee80211_get_channel(struct wiphy *wiphy,
>  	int i;
>  
>  	for (band = 0; band < IEEE80211_NUM_BANDS; band++) {
> -		sband = wiphy->bands[band];
> +		sband = wiphy ? wiphy->bands[band] : NULL;
>  
>  		if (!sband)
>  			continue;
> 

I am curious why wiphy can be null, is there some underlying bug
somewhere else that is the root cause than needs fixing rather than
papering over the issue with these workarounds?

Colin