On Fri, Oct 12, 2012 at 1:13 PM, Stanislaw Gruszka <sgruszka@redhat.com> wrote:
> On Tue, Oct 09, 2012 at 10:14:40AM +0100, Pedro Francisco wrote:
>> So, I'm guessing this means it is related to what you found on iwlwifi
>> (even if I'm on iwlegacy)?
>
> Yes, this seems to be cfg80211 problem. I think crash happen because
> cfg80211 is in disassociate state (i.e. has wdev->current_bss NULL) and
> erroneously mac80211 stays in associate state. So while we unload
> module cfg80211_mlme_down() we do not call ieee80211_deauth().
>
> I think this state mishmash happens because wrong behaviour on
>  __cfg80211_mlme_deauth(). Below patch try to correct that.
> Can you check if it prevent a crash? On my environment I can
> not reproduce this problem reliably.
>
> Thanks
> Stanislaw
>
> diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
> index ab78b53..9b99b60 100644
> --- a/include/net/cfg80211.h
> +++ b/include/net/cfg80211.h
> @@ -1218,6 +1218,7 @@ struct cfg80211_deauth_request {
>         const u8 *ie;
>         size_t ie_len;
>         u16 reason_code;
> +       bool local_state_change;
>  };
>
>  /**
> diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c
> index e714ed8..e510a33 100644
> --- a/net/mac80211/mlme.c
> +++ b/net/mac80211/mlme.c
> @@ -3549,6 +3549,7 @@ int ieee80211_mgd_deauth(struct ieee80211_sub_if_data *sdata,
>  {
>         struct ieee80211_if_managed *ifmgd = &sdata->u.mgd;
>         u8 frame_buf[IEEE80211_DEAUTH_FRAME_LEN];
> +       bool tx = !req->local_state_change;
>
>         mutex_lock(&ifmgd->mtx);
>
> @@ -3565,12 +3566,12 @@ int ieee80211_mgd_deauth(struct ieee80211_sub_if_data *sdata,
>         if (ifmgd->associated &&
>             ether_addr_equal(ifmgd->associated->bssid, req->bssid)) {
>                 ieee80211_set_disassoc(sdata, IEEE80211_STYPE_DEAUTH,
> -                                      req->reason_code, true, frame_buf);
> +                                      req->reason_code, tx, frame_buf);
>         } else {
>                 drv_mgd_prepare_tx(sdata->local, sdata);
>                 ieee80211_send_deauth_disassoc(sdata, req->bssid,
>                                                IEEE80211_STYPE_DEAUTH,
> -                                              req->reason_code, true,
> +                                              req->reason_code, tx,
>                                                frame_buf);
>         }
>
> diff --git a/net/wireless/mlme.c b/net/wireless/mlme.c
> index 3df195a..4954010 100644
> --- a/net/wireless/mlme.c
> +++ b/net/wireless/mlme.c
> @@ -457,21 +457,11 @@ int __cfg80211_mlme_deauth(struct cfg80211_registered_device *rdev,
>                 .reason_code = reason,
>                 .ie = ie,
>                 .ie_len = ie_len,
> +               .local_state_change = local_state_change,
>         };
>
>         ASSERT_WDEV_LOCK(wdev);
>
> -       if (local_state_change) {
> -               if (wdev->current_bss &&
> -                   ether_addr_equal(wdev->current_bss->pub.bssid, bssid)) {
> -                       cfg80211_unhold_bss(wdev->current_bss);
> -                       cfg80211_put_bss(&wdev->current_bss->pub);
> -                       wdev->current_bss = NULL;
> -               }
> -
> -               return 0;
> -       }
> -
>         return rdev->ops->deauth(&rdev->wiphy, dev, &req);
>  }
>

I've been testing the patch since this morning (GMT), I can't
reproduce any of the issues I referred on this thread (had to adapt
the patch slightly, though). Seems to be fixed!

Thank you for your help!
-- 
Pedro Francisco