Message-ID: <1431348378.1964.27.camel@sipsolutions.net> (sfid-20150511_144629_999105_092EE8DC)
Subject: Re: [PATCH] mac80211: WEP, move tailroom size check
From: Johannes Berg <johannes@sipsolutions.net>
To: Michal Kazior <michal.kazior@tieto.com>
Cc: Janusz Dziedzic <janusz.dziedzic@tieto.com>,
	linux-wireless <linux-wireless@vger.kernel.org>
Date: Mon, 11 May 2015 14:46:18 +0200
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On Mon, 2015-05-11 at 14:43 +0200, Michal Kazior wrote:
> On 11 May 2015 at 14:08, Johannes Berg <johannes@sipsolutions.net> wrote:
> > On Mon, 2015-05-11 at 11:31 +0200, Janusz Dziedzic wrote:
> >> Remove checking tailroom when adding IV, while
> >> this goes to headroom. Move this check to the function
> >> that will generate/put ICV for WEP.
> >>
> >> In other case I hit such warning and datapath don't work,
> >> when testing:
> >> - IBSS + WEP
> >> - ath9k with hw crypt enabled
> >> - IPv6 data (ping6)
> >
> > Is this new, perhaps due to fast-xmit, because we previously added
> > tailroom for WEP always? I've certainly never seen this before.
> >
> > (just asking so I know where it needs to be applied)
> 
> I think this was hidden for quite some time now, possibly since
> _PUT_IV_SPACE and _GENERATE_IV were split into _GENERATE_MMIC and
> _RESERVE_TAILROOM counterparts. I know that `ping` didn't trigger this
> problem, instead `ping6` did which leads me to think that maybe
> sk_buff allocation was getting lucky most of the time.

Ok, let's mark it for stable then, it's clearly fixing a bug :)

johannes