Messages in this thread |  | | | Date | Tue, 30 May 2006 19:11:18 +0200 | | From | Dominik Brodowski <> | | Subject | Re: [patch 00/61] ANNOUNCE: lock validator -V1 |
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Hi,
On Tue, May 30, 2006 at 10:58:52AM -0400, Dave Jones wrote: > On Tue, May 30, 2006 at 04:19:22PM +0200, Arjan van de Ven wrote: > > > > > One > > > > --- > > > > store_scaling_governor takes policy->lock and then calls __cpufreq_set_policy > > > > __cpufreq_set_policy calls __cpufreq_governor > > > > __cpufreq_governor calls __cpufreq_driver_target via cpufreq_governor_performance > > > > __cpufreq_driver_target calls lock_cpu_hotplug() (which takes the hotplug lock) > > > > > > > > > > > > Two > > > > --- > > > > cpufreq_stats_init lock_cpu_hotplug() and then calls cpufreq_stat_cpu_callback > > > > cpufreq_stat_cpu_callback calls cpufreq_update_policy > > > > cpufreq_update_policy takes the policy->lock > > > > > > > > > > > > so this looks like a real honest AB-BA deadlock to me... > > > > > > This looks a little clearer this morning. I missed the fact that sys_init_module > > > isn't completely serialised, only the loading part. ->init routines can and will be > > > called in parallel. > > > > > > I don't see where cpufreq_update_policy takes policy->lock though. > > > In my tree it just takes the per-cpu data->lock. > > > > isn't that basically the same lock? > > Ugh, I've completely forgotten how this stuff fits together. > > Dominik, any clues ?
That's indeed a possible deadlock situation -- what's the cpufreq_update_policy() call needed for in cpufreq_stat_cpu_callback anyway?
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