Re: bug in commit: mac80211: Fix possible sband related NULL pointer de-reference

[Ben Greear <greearb@candelatech.com>]

On 11/17/2017 02:30 PM, Ben Greear wrote:
> Author: Mohammed Shafi Shajakhan <mohammed@qti.qualcomm.com>
> Date:   Thu Apr 27 12:45:38 2017 +0530
>
>     mac80211: Fix possible sband related NULL pointer de-reference
>
>     Existing API 'ieee80211_get_sdata_band' returns default 2 GHz band even
>     if the channel context configuration is NULL. This crashes for chipsets
>     which support 5 Ghz alone when it tries to access members of 'sband'.
>     Channel context configuration can be NULL in multivif case and when
>     channel switch is in progress (or) when it fails. Fix this by replacing
>     the API 'ieee80211_get_sdata_band' with  'ieee80211_get_sband' which
>     returns a NULL pointer for sband when the channel configuration is NULL.
>
> ...
>
> This commit appears to break  sta_set_rate_info_tx on drivers that are not using chantx,
> because it calls ieee80211_get_sband, which does a WARN_ON when there is no chantx.
>
> Any idea how to make this work for chandef drivers?

Maybe there are other issues in my case.  I'll test out a patch to make it WARN_ON_ONCE
and submit once I get some other problems ironed out.

Thanks,
Ben

-- 
Ben Greear <greearb@candelatech.com>
Candela Technologies Inc  http://www.candelatech.com