Re: [3.2-rc3] 100% CPU usage while in del_timer_sync from iwl3945_rs_free_sta

From: Sedat Dilek
Date: Thu Dec 01 2011 - 08:37:56 EST


On Thu, Dec 1, 2011 at 2:13 PM, Eliad Peller <eliad@xxxxxxxxxx> wrote:
> On Thu, Dec 1, 2011 at 2:55 PM, Stanislaw Gruszka <sgruszka@xxxxxxxxxx> 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:
>>> > > [ Â349.316070] iwl3945_rs_free_sta rs_sta f4be1ac0
>>> > > [ Â349.316076] ------------[ cut here ]------------
>>> > > [ Â349.316097] 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@xxxxxxxxxx>
>>> > Date: Â Mon Aug 8 16:50:22 2011 +0300
>>> >
>>> > Â Â 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, Âand 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?
>

Isnt't the mainline handling "user-friendliness first" by reverting
"buggy" commits (especially if there is no fix/patch in sight)?
A proper fix can be done later.
Just my 2 cents.

- Sedat -

> Eliad.
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