Messages in this thread |  | | Date | Tue, 21 Oct 2014 11:10:43 -0400 | From | Dave Jones <> | Subject | Re: lockdep splat in CPU hotplug |
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On Tue, Oct 21, 2014 at 01:09:04PM +0200, Jiri Kosina wrote: > Hi, > > I am seeing the lockdep report below when resuming from suspend-to-disk > with current Linus' tree (c2661b80609). > > The reason for CCing Ingo and Peter is that I can't make any sense of one > of the stacktraces lockdep is providing. > > Please have a look at the very first stacktrace in the dump, where lockdep > is trying to explain where cpu_hotplug.lock#2 has been acquired. It seems > to imply that cpuidle_pause() is taking cpu_hotplug.lock, but that's not > the case at all.
Could inlining be confusing the trace here ?
You can get from cpuidle_pause to cpuidle_uninstall_idle_handler -> synchronize_rcu -> synchronize_sched -> synchronize_sched_expedited which does a try_get_online_cpus which will take the cpu_hotplug.lock
Dave
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