Return-path: Received: from cantor2.suse.de ([195.135.220.15]:59958 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753833Ab1LAMms (ORCPT ); Thu, 1 Dec 2011 07:42:48 -0500 Date: Thu, 1 Dec 2011 13:42:44 +0100 From: Michal Hocko To: Yong Zhang Cc: Stanislaw Gruszka , 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: <20111201124244.GA25614@tiehlicka.suse.cz> (sfid-20111201_134306_372284_EA7A94EC) References: <20111129100727.GD2675@tiehlicka.suse.cz> <20111129113906.GA7299@redhat.com> <20111130101028.GA2906@tiehlicka.suse.cz> <20111130142316.GA2466@redhat.com> <20111130140316.GA4153@tiehlicka.suse.cz> <20111130153929.GA2144@redhat.com> <20111201085845.GA4602@tiehlicka.suse.cz> <20111201105538.GA4504@tiehlicka.suse.cz> <20111201120400.GA2112@zhy> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <20111201120400.GA2112@zhy> Sender: linux-wireless-owner@vger.kernel.org List-ID: On Thu 01-12-11 20:04:01, Yong Zhang wrote: > On Thu, Dec 01, 2011 at 11:55:38AM +0100, Michal Hocko wrote: > > On Thu 01-12-11 09:58:45, Michal Hocko wrote: > > [...] > > > I will try to turn on timer debugging suggested by Yong Zhang in other > > > email. > > > > OK, so applied the following commits: > > $ git shortlog master.. > > Christine Chan (2): > > timer: Use debugobjects to catch deletion of uninitialized timers > > debugobjects: Extend to assert that an object is initialized > > > > Michal Hocko (1): > > Debugging patch > > > > Stephen Boyd (2): > > timer: Setup uninitialized timer with a stub callback > > debugobjects: Be smarter about static objects > > > > Debugging patch is the one from Stanislaw posted earlier in the thread. > > It prevents del_timer_sync and warns on NULL timer in iwl3945_rs_free_sta. > > Also turned on the suggested DEBUG_OBJECTS_TIMERS. > > > > I do not see any timer related warnings. I will try it with the slightly > > modified Debugging patch and just warn without returning before calling > > del_timer_sync. > > > > [ 349.316076] ------------[ cut here ]------------ > > [ 349.316097] WARNING: at drivers/net/wireless/iwlegacy/iwl-3945-rs.c:438 iwl3945_rs_free_sta+0x33/0x42 [iwl3945]() > > [ 349.316105] Hardware name: LIFEBOOK S7110 > > [ 349.316110] Modules linked in: aes_i586 aes_generic i915 fbcon font bitblit softcursor drm_kms_helper drm fb fbdev i2c_algo_bit cfbcopyarea i2c_core cfbimgblt cfbfillrect fuse tun coretemp hwmon snd_hda_codec_realtek arc4 snd_hda_intel snd_hda_codec snd_pcm_oss snd_mixer_oss iwl3945 snd_pcm iwl_legacy snd_seq_oss snd_seq_midi_event mac80211 snd_seq snd_timer snd_seq_device cfg80211 snd video snd_page_alloc fujitsu_laptop backlight [last unloaded: scsi_wait_scan] > > [ 349.316203] Pid: 12, comm: kworker/u:1 Tainted: G W 3.2.0-rc3-timerstest-00009-g762dd0e #20 > > ^ > seems there was warning but we did't catch it, right? > not sure if it's related. Not related. It is just the previous attempt. I just forgot to set loglevel before the first test. -- Michal Hocko SUSE Labs SUSE LINUX s.r.o. Lihovarska 1060/12 190 00 Praha 9 Czech Republic