Re: [PATCH] mac80211: disassociate when switching bands and not scanning

[reinette chatre <reinette.chatre@intel.com>]

Hi Luis,

On Wed, 2009-06-10 at 13:49 -0700, Luis R. Rodriguez wrote:
> On Wed, Jun 10, 2009 at 1:49 PM, reinette
> chatre<reinette.chatre@intel.com> wrote:
> > Hi Luis,
> >
> > On Wed, 2009-06-10 at 13:35 -0700, Luis R. Rodriguez wrote:
> >> If we're associated to an AP and we manually decide to switch
> >> bands we have no guarantee we can communicate with that AP
> >> on the new band and our current bss parameters may change
> >> completely so disassociate.
> >>
> >> This fixes this warning (which is not specific to iwlwifi!):
> >>
> >> [25612.559460] ------------[ cut here ]------------
> >> [25612.559500] WARNING: at include/net/mac80211.h:2127 rate_control_send_low+0xcf/0xe0 [mac80211]()
> >> [25612.559508] Hardware name: VGN-N170G
> >> [25612.559513] Modules linked in: ath9k ath mac80211 cfg80211 <bleh line cut>
> >> [25612.559807] Pid: 14492, comm: iwconfig Not tainted 2.6.30-rc8-wl #11
> >> [25612.559814] Call Trace:
> >> [25612.559829]  [<c03b2cd9>] ? printk+0x18/0x1f
> >> [25612.559865]  [<f831072f>] ? rate_control_send_low+0xcf/0xe0 [mac80211]
> >> [25612.559878]  [<c0134f4c>] warn_slowpath_common+0x6c/0xc0
> >> [25612.559912]  [<f831072f>] ? rate_control_send_low+0xcf/0xe0 [mac80211]
> >> [25612.559923]  [<c0134fb5>] warn_slowpath_null+0x15/0x20
> >> [25612.559957]  [<f831072f>] rate_control_send_low+0xcf/0xe0 [mac80211]
> >> [25612.559985]  [<f84129c3>] ath_get_rate+0x33/0x520 [ath9k]
> >> [25612.559998]  [<c015cb73>] ? mark_held_locks+0x63/0x80
> >> [25612.560064]  [<f831057d>] rate_control_get_rate+0xbd/0xd0 [mac80211]
> >> [25612.560102]  [<f8318b6f>] invoke_tx_handlers+0x5df/0xfa0 [mac80211]
> >> [25612.560115]  [<c015cb73>] ? mark_held_locks+0x63/0x80
> >> [25612.560152]  [<f8317854>] ? __ieee80211_tx_prepare+0x194/0x3b0 [mac80211]
> >> [25612.560190]  [<f8319796>] ieee80211_tx+0xd6/0x280 [mac80211]
> >> [25612.560227]  [<f831972f>] ? ieee80211_tx+0x6f/0x280 [mac80211]
> >> [25612.560265]  [<f8319e39>] ieee80211_master_start_xmit+0x1f9/0x400 [mac80211]
> >> [25612.560280]  [<c032347b>] dev_hard_start_xmit+0x2ab/0x340
> >> [25612.560292]  [<c0323230>] ? dev_hard_start_xmit+0x60/0x340
> >> [25612.560304]  [<c0335675>] __qdisc_run+0x1e5/0x240
> >> [25612.560316]  [<c03245d7>] dev_queue_xmit+0x377/0x4e0
> >> [25612.560328]  [<c0324298>] ? dev_queue_xmit+0x38/0x4e0
> >> [25612.560365]  [<f831c1d2>] ieee80211_tx_skb+0x52/0x60 [mac80211]
> >> [25612.560400]  [<f83079d0>] ieee80211_send_delba+0xf0/0x150 [mac80211]
> >> [25612.560413]  [<c013f931>] ? del_timer_sync+0x81/0xb0
> >> [25612.560447]  [<f830903a>] __ieee80211_stop_rx_ba_session+0xea/0x1d0 [mac80211]
> >> [25612.560476]  [<f8409310>] ? ath9k_ampdu_action+0x0/0x130 [ath9k]
> >> [25612.560511]  [<f8307a63>] ieee80211_sta_tear_down_BA_sessions+0x33/0x40 [mac80211]
> >> [25612.560548]  [<f830afd8>] ieee80211_set_disassoc+0xc8/0x370 [mac80211]
> >> [25612.560583]  [<f830af10>] ? ieee80211_set_disassoc+0x0/0x370 [mac80211]
> >> [25612.560597]  [<c01ace6b>] ? might_fault+0x4b/0xa0
> >> [25612.560632]  [<f830b580>] ieee80211_sta_req_auth+0xa0/0xc0 [mac80211]
> >> [25612.560665]  [<f8303fde>] ieee80211_ioctl_siwessid+0xbe/0xd0 [mac80211]
> >> [25612.560679]  [<c02749c5>] ? copy_from_user+0x35/0x130
> >> [25612.560694]  [<c039d819>] ioctl_standard_call+0x199/0x3a0
> >> [25612.560707]  [<c032358d>] ? __dev_get_by_name+0x7d/0xa0
> >> [25612.560720]  [<c039d31f>] wext_handle_ioctl+0x14f/0x230
> >> [25612.560753]  [<f8303f20>] ? ieee80211_ioctl_siwessid+0x0/0xd0 [mac80211]
> >> [25612.560766]  [<c0324114>] dev_ioctl+0x474/0x540
> >> [25612.560780]  [<c019f685>] ? __pagevec_free+0x25/0x30
> >> [25612.560794]  [<c0312350>] ? sock_ioctl+0x0/0x270
> >> [25612.560806]  [<c0312445>] sock_ioctl+0xf5/0x270
> >> [25612.560817]  [<c0312350>] ? sock_ioctl+0x0/0x270
> >> [25612.560831]  [<c01d9018>] vfs_ioctl+0x28/0x90
> >> [25612.560843]  [<c01d90f2>] do_vfs_ioctl+0x72/0x590
> >> [25612.560856]  [<c015ce8b>] ? trace_hardirqs_on+0xb/0x10
> >> [25612.560868]  [<c01b2a16>] ? remove_vma+0x56/0x70
> >> [25612.560879]  [<c01b2a16>] ? remove_vma+0x56/0x70
> >> [25612.560890]  [<c01b38f7>] ? do_munmap+0x237/0x290
> >> [25612.560902]  [<c0103021>] ? sysenter_exit+0xf/0x1a
> >> [25612.560914]  [<c01d9673>] sys_ioctl+0x63/0x70
> >> [25612.560925]  [<c0102fec>] sysenter_do_call+0x12/0x38
> >> [25612.560934] ---[ end trace 05e1ecc810d6b568 ]---
> >> [25612.561114] ------------[ cut here ]------------
> >>
> >> Cc: Reinette Chatre <reinette.chatre@intel.com>
> >> Cc: Zhu Yi <yi.zhu@intel.com>
> >> Cc: Mohamed Abbas <mohamed.abbas@intel.com>
> >> Cc: ipw3945-devel@lists.sourceforge.net
> >> Signed-off-by: Luis R. Rodriguez <lrodriguez@atheros.com>
> >> ---
> >>  net/mac80211/util.c |   17 ++++++++++++++++-
> >>  1 files changed, 16 insertions(+), 1 deletions(-)
> >>
> >> diff --git a/net/mac80211/util.c b/net/mac80211/util.c
> >> index 66ce96a..8e66556 100644
> >> --- a/net/mac80211/util.c
> >> +++ b/net/mac80211/util.c
> >> @@ -791,9 +791,24 @@ int ieee80211_set_freq(struct ieee80211_sub_if_data *sdata, int freqMHz)
> >>
> >>               if (local->sw_scanning || local->hw_scanning)
> >>                       ret = 0;
> >> -             else
> >> +             else {
> >> +                     struct ieee80211_channel *cur_chan;
> >> +
> >> +                     cur_chan = local->hw.conf.channel;
> >> +
> >> +                     /*
> >> +                      * If we're switching bands and not scanning we
> >> +                      * could potentially be moving to a band our AP
> >> +                      * does not understand so give up on it
> >> +                      */
> >> +                     if (sdata->vif.type == NL80211_IFTYPE_STATION &&
> >> +                         (sdata->u.mgd.flags & IEEE80211_STA_ASSOCIATED) &&
> >> +                         cur_chan->band != chan->band)
> >> +                             ieee80211_sta_deauthenticate(sdata,
> >> +                                     WLAN_REASON_DEAUTH_LEAVING);
> >>                       ret = ieee80211_hw_config(
> >>                               local, IEEE80211_CONF_CHANGE_CHANNEL);
> >> +             }
> >>       }
> >>
> >>       return ret;
> >
> > This touches code targeted for removal in recent "mac80211: disconnect
> > when user changes channel" patch.
> 
> Heh I don't see that patch yet but if it exists that should fix this
> too unless that patch didn't deauth/disassoc. Did you try with it
> applied by any chance? I can't seem to find that patch on the list.

That patch does seem to have same intention as yours. It is still RFC so
I am not sure about its status. I did not test with it, but will do so.
The patch can be found at
http://marc.info/?l=linux-wireless&m=124458448631186&w=2

Reinette