Well, I've added the following code to cpufreq_register_notifier()
(drivers/cpufreq/cpufreq.c) to CPUFREQ_TRANSITION_NOTIFIER case:
===
pr_info("Registered transition notifier: %p, (%p)\n", nb->notifier_call, &nb-
>notifier_call);
===
And got the following in my dmesg (only 1 line):
===
$ cat /var/log/kern.log | grep "Registered transition notifier"
Aug 12 17:23:45 defiant kernel: [ 3.084977] cpufreq: Registered transition
notifier: ffffffff81590378, (ffffffff81cb0ba0)
===
System.map tells me, that ffffffff81590378 corresponds to
cpufreq_stat_notifier_trans() (in drivers/cpufreq/cpufreq_stats.c).
Also I've added
===
pr_info("%s\n", __func__);
===
to all callbacks (hello, LXR :)), and got the following occurrences in dmesg:
===
$ cat /var/log/kern.log | egrep -e '(acpi_|cpufreq|notifier)' | awk
'{print($7)}' | sort -u
acpi_processor_ppc_notifier
acpi_thermal_cpufreq_notifier
cpufreq_stat_notifier_policy
===
No extra notifiers are involved so far, but also I haven't caught new hang yet
as it occurs randomly. Still waiting for it, but I hope my little
investigation could help somehow.
On Tuesday 12 August 2014 13:16:25 Viresh Kumar wrote:
> On Tue, Aug 12, 2014 at 12:56 PM, Oleksandr Natalenko
>
> <oleksa...@natalenko.name> wrote:
> > Got that and will try to investigate ASAP.
> >
> > Just to note: I tried to use powersave governor and got the same result. I
> > believe notifiers are used with powersave governor as well. Am I wrong?
> Notifiers are used from the cpufreq core when frequency is changed.
> And the powersave governor should have changed the frequency only
> ONCE, i.e. to go to lowest frequency.
>
> So, it probably happened at the first & only change at that time as well..
> But it shouldn't happen any later. So, see what the log looks like on
> that crash.
--
Oleksandr post-factum Natalenko, MSc
pf-kernel community
https://natalenko.name/
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