Return-path: Received: from cantor2.suse.de ([195.135.220.15]:36079 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753042Ab1K3KKc (ORCPT ); Wed, 30 Nov 2011 05:10:32 -0500 Date: Wed, 30 Nov 2011 11:10:28 +0100 From: Michal Hocko To: Stanislaw Gruszka 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: <20111130101028.GA2906@tiehlicka.suse.cz> (sfid-20111130_111053_261824_4B367AD2) References: <20111129100727.GD2675@tiehlicka.suse.cz> <20111129113906.GA7299@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <20111129113906.GA7299@redhat.com> Sender: linux-wireless-owner@vger.kernel.org List-ID: On Tue 29-11-11 12:39:07, Stanislaw Gruszka wrote: > Hi Michal > > 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? > 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. > If so I'll try to reproduce it locally, otherwise I'll review related > code to find reason of that problem. > > Thanks > Stanislaw Thanks -- Michal Hocko SUSE Labs SUSE LINUX s.r.o. Lihovarska 1060/12 190 00 Praha 9 Czech Republic