Re: Bisected 3.9 regression for iwl4965 connection problem to 1672c0e3

Stanislaw Gruszka
2013-05-22T11:57:31Z

On Tue, May 07, 2013 at 05:35:25PM +0200, Stanislaw Gruszka wrote:
> On Tue, May 07, 2013 at 03:53:30PM +0200, Johannes Berg wrote:
> > > I'm not sure if I like to add passive_no_rx to iwlegacy. Stopping queues
> > > and waiting for beacon looks sticky, what happen if beacon will not be
> > > received?
> >
> > Good question, do we get stuck? I was assuming we'd time out, but maybe
> > that's not the case?
>
> AFICT, we wake queues only if beacon arrives or mac80211 call drv_config
> with BSS_CHANGED_IDLE. I'm not sure if the latter prevent stuck.

It should prevent stuck. When we fail to auth, drv_config() with BSS_CHANGED_IDLE
is called via:

ieee80211_destroy_auth_data ->
ieee80211_vif_release_channel ->
__ieee80211_vif_release_channel ->
ieee80211_unassign_vif_chanctx ->
ieee80211_bss_info_change_notify

But there is need to have ->vif.chanctx_conf valid in
__ieee80211_vif_release_channel(), where is below condition:

conf = rcu_dereference_protected(sdata->vif.chanctx_conf,
lockdep_is_held(&local->chanctx_mtx));
if (!conf)
return;

I'm not sure if that always happen. Perhaps would be better to change
BSS_CHANGED_IDLE to BSS_CHANGED_BSSID, which is called directly from
ieee80211_destroy_auth_data() ?

Stanislaw