Re: [PATCH 3/3] p54: zero-out rx_status

[Gabor Juhos <juhosg@openwrt.org>]

2012.12.11. 16:08 keltezéssel, Christian Lamparter írta:
> On Tuesday, December 11, 2012 02:55:05 PM Gabor Juhos wrote:
>> In commit 'mac80211: support radiotap vendor namespace RX data'
>> new fields were added to 'struct ieee80211_rx_status'.
>> The ath5k driver does not initializes those fields and
>       ^^^^^ p54?!

Of course.

>> this can cause unexpected behaviour. The patch ensures
>> that each field gets initialized with zeroes.
> 
> Actually, when the skb is alloced/initialized by
> __alloc_skb, the skb->cb is already zeroed

Thank you for the explanation, I was not aware of this.

> (which is where the ieee80211_rx_status will be stored).
> 
> And while p54 recycles command response skbs, the 
> driver does not touch the skb->cb of 802.11 skbs,
> until the frame is destined for ieee80211_rx_irqsave.

Ok.

> If this issue just popped up now, I suspect that 
> something else is silently corrupting our SKBs 
> [or can anybody see how rt2x00 hit this issue?]

It is popped up now because we have switched to compat-wireless-2012-12-06 in
OpenWrt a few days ago. Previously we were using compat-wireless-2012-09-07.

-Gabor