Re: [PATCH wireless-next v2] net: cfg80211: validate monitor channel set against radio usage

[Rory Little <roryl@candelatech.com>]

On 9/21/26 13:20, Johannes Berg wrote:
> On Mon, 2026-09-21 at 13:17 -0700, Rory Little wrote:
>>>> - Handle error return from cfg80211_get_radio_idx_by_chan
>>> Yes, but did you do it correctly? I don't think so?
>> You mean propagating -EINVAL out to the caller, right? I'd need to
>> handle the n_radio == 0 case to keep the -EBUSY behavior consistent.
> Yeah, I get that, but it seemed tgo me it should return true (accepting
> the channel change) - but then again maybe not, since it already accepts
> "only have monitors", and then getting there means there's something
> else ... sorry.

Yeah, if we are there then there are other interfaces up, so rejecting 
at that point keeps the existing behavior. I'll add a comment clarifying 
that.

On a different note, I also noticed that this introduced an issue - 
cfg80211_has_monitors_only also verifies that there is at least one 
active interface. This patch loses that verification for multi-radio 
wiphys. I will fix this in v3.

- Rory