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Date: Thu, 1 Dec 2011 15:13:42 +0200
Message-ID: <CAB3XZEeNF8_U__rOPMfiOFNjPTS6gb33CSjdwkhMdRmS+i3CTw@mail.gmail.com> (sfid-20111201_141403_026710_6E0FF4AE)
Subject: Re: [3.2-rc3] 100% CPU usage while in del_timer_sync from iwl3945_rs_free_sta
From: Eliad Peller <eliad@wizery.com>
To: Stanislaw Gruszka <sgruszka@redhat.com>
Cc: Michal Hocko <mhocko@suse.cz>, LKML <linux-kernel@vger.kernel.org>,
	"John W. Linville" <linville@tuxdriver.com>,
	linux-wireless@vger.kernel.org, Yong Zhang <yong.zhang0@gmail.com>
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Sender: linux-wireless-owner@vger.kernel.org

On Thu, Dec 1, 2011 at 2:55 PM, Stanislaw Gruszka <sgruszka@redhat.com> wrote:
> On Thu, Dec 01, 2011 at 01:44:40PM +0100, Michal Hocko wrote:
>> On Thu 01-12-11 12:59:12, Stanislaw Gruszka wrote:
>> > On Thu, Dec 01, 2011 at 11:55:38AM +0100, Michal Hocko wrote:
>> > > [ ?349.316070] iwl3945_rs_free_sta rs_sta f4be1ac0
>> > > [ ?349.316076] ------------[ cut here ]------------
>> > > [ ?349.316097] WARNING: at drivers/net/wireless/iwlegacy/iwl-3945-rs.c:438 iwl3945_rs_free_sta+0x33/0x42 [iwl3945]()
>> >
>> > Johannes pointed on irc that this problem is most likely caused by:
>> >
>> > commit f785d83a19bca326f79d127a413e35769afc0105
>> > Author: Eliad Peller <eliad@wizery.com>
>> > Date: ? Mon Aug 8 16:50:22 2011 +0300
>> >
>> > ? ? mac80211: clear sta.drv_priv on reconfiguration
>> >
>> > Michal, could you confirm that? If that is the root of the problem, we
>> > need patch for iwlegacy (and iwlwifi) that allocate separate memory for
>> > rc structures.
> Actually this require quite big changes in iwlegacy at least, perhaps
> also in iwlwifi. I prefer to revert commit as temporary fix, ?and add
> memset(0) to drivers .add_sta callback, in drivers which need it. After
> changing iwlegcy/iwlwifi we could move memset(0) back to ieee80211_reconfig().
>
> Eliad, thoughts?
>
i don't really care about temporarily reverting it.
but maybe you can just add an "initialized" flag to iwl3945_rs_sta,
and check it on free_sta?

Eliad.