Re: 2.6.32-rc5-mmotm1101 - lockdep whinge during early boot

From: Thomas Gleixner
Date: Thu Nov 05 2009 - 09:55:37 EST

On Thu, 5 Nov 2009, Oleg Nesterov wrote:
> > Oleg (CC'd) made workqueues use cpu_maps_update_begin() instead of the
> > more obvious get_online_cpus() in 3da1c84c00c7e5f. Reverting that seems like
> > a bad idea.
> Even if create_workueue() used get_online_cpus() instead of cpu_add_remove_lock,
> we have the same problem: _cpu_up() takes cpu_hotplug.lock which is needed for
> get_online_cpus(). The dependency above becomes:
> cpu_up()->clocksource_change_rating() takes clocksource_mutex under
> cpu_hotplug.lock (cpu_hotplug_begin)
> clocksource_done_booting()->create_workueue() takes cpu_hotplug.lock
> (get_online_cpus) under clocksource_mutex

Hmm, we fixed all this lock madness in mainline already.
clocksource_done_booting() does not longer call
create_workqueue(). How got this code reverted in motm ?


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