Re: mac80211: 3.9.0+: Invalid WDS/flush state and non-connecting station.

[Ben Greear <greearb@candelatech.com>]

On 05/02/2013 01:45 PM, Ben Greear wrote:
> On 05/02/2013 01:24 PM, Johannes Berg wrote:
>> On Thu, 2013-05-02 at 12:50 -0700, Ben Greear wrote:
>>> Kernel is hacked 3.9.0+
>>
>> Clearly :)
>>
>>> I've been seeing this problem for a while (and posted about it previously).  The problem
>>> is that a station appears to associate fine, but never actually 'connects'.  This problem
>>> is not easy to reproduce...
>>
>> It would be useful to know what you added ... the message you point to
>> (invalid wds/flush whatever) doesn't exist upstream.
>
> Gobs of stuff, as usual.  Thought I had that WDS thing pushed upstream,
> but I guess not.

Ok, I reproduced this with yet more debugging printouts in the kernel.

The symptom is this:

The sme_state is SME_CONNECTED, so it bails out below before sending the
'connected' message to user-space.

void __cfg80211_connect_result(struct net_device *dev, const u8 *bssid,
                                const u8 *req_ie, size_t req_ie_len,
                                const u8 *resp_ie, size_t resp_ie_len,
                                u16 status, bool wextev,
                                struct cfg80211_bss *bss)
{
         struct wireless_dev *wdev = dev->ieee80211_ptr;
         const u8 *country_ie;
#ifdef CONFIG_CFG80211_WEXT
         union iwreq_data wrqu;
#endif

         ASSERT_WDEV_LOCK(wdev);

         printk("connect_result: %s: type: %i  sme_state: %i\n",
                dev->name, (int)(wdev->iftype), (int)(wdev->sme_state));

         if (WARN_ON(wdev->iftype != NL80211_IFTYPE_STATION &&
                     wdev->iftype != NL80211_IFTYPE_P2P_CLIENT))
                 return;

         if (wdev->sme_state != CFG80211_SME_CONNECTING)
                 return;

>
> http://dmz2.candelatech.com/git/gitweb.cgi?p=linux-3.9.dev.y/.git;a=summary
>
> That message comes from:
>
>      /*
>       * Remove all stations associated with this interface.
>       *
>       * This must be done before calling ops->remove_interface()
>       * because otherwise we can later invoke ops->sta_notify()
>       * whenever the STAs are removed, and that invalidates driver
>       * assumptions about always getting a vif pointer that is valid
>       * (because if we remove a STA after ops->remove_interface()
>       * the driver will have removed the vif info already!)
>       *
>       * This is relevant only in WDS mode, in all other modes we've
>       * already removed all stations when disconnecting or similar,
>       * so warn otherwise.
>       *
>       * We call sta_info_flush_cleanup() later, to combine RCU waits.
>       */
>      flushed = sta_info_flush_defer(sdata);
>      if ((sdata->vif.type != NL80211_IFTYPE_WDS && flushed > 0) ||
>          (sdata->vif.type == NL80211_IFTYPE_WDS && flushed != 1)) {
>          sdata_info(sdata,
>                 "Invalid WDS/flush state, type: %i  WDS: %i  flushed: %i\n",
>                 sdata->vif.type, NL80211_IFTYPE_WDS, flushed);
>          WARN_ON_ONCE(1);
>      }
>
> I notice __cfg80211_connect_result checks the wdev state, so I added some
> printouts there to see if it is bailing due to some funny state, but will
> probably be a while before I reproduce it again and know for sure.
>
> Thanks,
> Ben
>
>
>>
>> johannes
>>
>
>


-- 
Ben Greear <greearb@candelatech.com>
Candela Technologies Inc  http://www.candelatech.com