Re: [PATCH] mac80211: do not call rate control .tx_status before .rate_init

[Pavel Roskin <proski@gnu.org>]

On Wed, 8 Feb 2012 14:44:54 -0500
"John W. Linville" <linville@tuxdriver.com> wrote:

> On Wed, Feb 08, 2012 at 08:38:00PM +0100, Felix Fietkau wrote:
> > On 2012-02-08 8:25 PM, John W. Linville wrote:
> > > On Wed, Feb 08, 2012 at 07:17:11PM +0100, Felix Fietkau wrote:
> > >> Most rate control implementations assume .get_rate
> > >> and .tx_status are only called once the per-station data has
> > >> been fully initialized. minstrel_ht crashes if this assumption
> > >> is violated.
> > >> 
> > >> Signed-off-by: Felix Fietkau <nbd@openwrt.org>
> > >> Tested-by: Arend van Spriel <arend@broadcom.com>
> > >> ---
> > >>  net/mac80211/rate.h |    2 +-
> > >>  1 files changed, 1 insertions(+), 1 deletions(-)
> > >> 
> > >> diff --git a/net/mac80211/rate.h b/net/mac80211/rate.h
> > >> index 5fc3135..fbb1efd 100644
> > >> --- a/net/mac80211/rate.h
> > >> +++ b/net/mac80211/rate.h
> > >> @@ -37,7 +37,7 @@ static inline void
> > >> rate_control_tx_status(struct ieee80211_local *local, struct
> > >> ieee80211_sta *ista = &sta->sta; void *priv_sta =
> > >> sta->rate_ctrl_priv; 
> > >> -	if (!ref)
> > >> +	if (!ref || !test_sta_flag(sta, WLAN_STA_RATE_CONTROL))
> > >>  		return;
> > >>  
> > >>  	ref->ops->tx_status(ref->priv, sband, ista, priv_sta,
> > >> skb);
> > > 
> > > Any reason not to apply this for 3.3?  Or stable?
> > I think 3.3 doesn't have that sta flag, the issue was probably
> > introduced with the 3.4 changes.
> > I don't remember something like this appearing in earlier versions.
> 
> Cool, thanks.

I believe 3.3 is affected.  At least it looks like the Fedora bug 768639
(https://bugzilla.redhat.com/show_bug.cgi?id=768639) is caused by
calling .tx_status at a wrong time.  Fedora kernels use
compat-wireless-3.3.  I'm going to test the bleeding edge
compat-wireless with the patch by Felix to see if it fixes things.

The lack of the WLAN_STA_RATE_CONTROL flag doesn't mean that the old
behavior was correct.  The flag was introduced to correct that behavior.

The oldest report is dated 2011-12-17 and it's about Linux 3.2.0-rc5
with compat-wireless-2011-12-01.

-- 
Regards,
Pavel Roskin