Return-path: Received: from mx1.redhat.com ([209.132.183.28]:47429 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752709Ab1K3NWj (ORCPT ); Wed, 30 Nov 2011 08:22:39 -0500 Date: Wed, 30 Nov 2011 15:23:16 +0100 From: Stanislaw Gruszka To: Michal Hocko Cc: LKML , "John W. Linville" , linux-wireless@vger.kernel.org Subject: Re: [3.2-rc3] 100% CPU usage while in del_timer_sync from iwl3945_rs_free_sta Message-ID: <20111130142316.GA2466@redhat.com> (sfid-20111130_142243_863912_80B3CC03) References: <20111129100727.GD2675@tiehlicka.suse.cz> <20111129113906.GA7299@redhat.com> <20111130101028.GA2906@tiehlicka.suse.cz> MIME-Version: 1.0 Content-Type: multipart/mixed; boundary="OgqxwSJOaUobr8KG" In-Reply-To: <20111130101028.GA2906@tiehlicka.suse.cz> Sender: linux-wireless-owner@vger.kernel.org List-ID: --OgqxwSJOaUobr8KG Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Wed, Nov 30, 2011 at 11:10:28AM +0100, Michal Hocko wrote: > On Tue 29-11-11 12:39:07, Stanislaw Gruszka wrote: > > On Tue, Nov 29, 2011 at 11:07:27AM +0100, Michal Hocko wrote: > > > [I am not sure whether this is ieee80211 or iwl3945 issue so put both > > > maintainers into loop] > > The only changed we had in iwlegacy between 3.1 and 3.2-rc, was only > > adjustment to mac80211 changes. However I think this is iwlegacy issue, > > just for some reason bug did not trigger before. > > I have double checked 3.1 and cannot reproduce it. > Anyway, I have put: > > diff --git a/drivers/net/wireless/iwlegacy/iwl-3945-rs.c b/drivers/net/wireless/iwlegacy/iwl-3945-rs.c > index 8faeaf2..9221ed4 100644 > --- a/drivers/net/wireless/iwlegacy/iwl-3945-rs.c > +++ b/drivers/net/wireless/iwlegacy/iwl-3945-rs.c > @@ -432,6 +432,7 @@ static void iwl3945_rs_free_sta(void *iwl_priv, struct ieee80211_sta *sta, > * to use iwl_priv to print out debugging) since it may not be fully > * initialized at this point. > */ > + printk("XXX: deleting time: %x\n", rs_sta->rate_scale_flush.base); > del_timer_sync(&rs_sta->rate_scale_flush); > } > > And the timer base is really NULL when the issue happens. So, somebody > probably removed the timer already? I think we call rs_ops->free_sta without rs_ops->alloc_sta, otherwise I don't know how it could be NULL in iwl3945_rs_free_sta (excluding memory corruption or bug in timer internals). I suspect this could be a regression introduced by commit: commit 07ba55d7f1d0da174c9bc545c713b44cee760197 Author: Arik Nemtsov Date: Wed Sep 28 14:12:53 2011 +0300 nl80211/mac80211: allow adding TDLS peers as stations I'm attaching patch with revert of relevant hunk, because full revert would be hard currently. Does it workaround problem for you? > > Is this problem 100% reproducible for you ? > > Yes, it seems to be sufficient to suspend to RAM while associated and > turn off the AP before waking up the machine. > I wasn't able to reproduce just by turning of the AP while associated > without suspend. I'm not able to recreate, but I'm not using your config as my system user-space has problem to startup with it :-( Stanislaw --OgqxwSJOaUobr8KG Content-Type: text/plain; charset=us-ascii Content-Disposition: attachment; filename="mac80211_use_sta_info_destroy_addr.patch" diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c index b1b1bb3..f773dbb 100644 --- a/net/mac80211/mlme.c +++ b/net/mac80211/mlme.c @@ -1144,9 +1144,8 @@ static void ieee80211_set_disassoc(struct ieee80211_sub_if_data *sdata, changed |= BSS_CHANGED_BSSID | BSS_CHANGED_HT; ieee80211_bss_info_change_notify(sdata, changed); - /* remove AP and TDLS peers */ if (remove_sta) - sta_info_flush(local, sdata); + sta_info_destroy_addr(sdata, bssid); del_timer_sync(&sdata->u.mgd.conn_mon_timer); del_timer_sync(&sdata->u.mgd.bcn_mon_timer); --OgqxwSJOaUobr8KG--