On Mon 2019-07-08 14:58:40, Viresh Kumar wrote: > On 08-07-19, 10:28, Rafael J. Wysocki wrote: > > Pavel has tested the latest version of the patch series AFAICS. > > > > The locking added by the commit in question to > > refresh_frequency_limits() requires an update of > > cpufreq_update_policy(), or it will deadlock in there because of the > > lock acquired by cpufreq_cpu_get() if I haven't missed anything. > > Ah, looks quite straight forward. > > @Pavel: Can you please try this diff ?
I tried to apply it on top of current next
(d58b5ab90ee7528126fd5833df7fc5bda8331ce8, 20190708) and linux-pm-next
(1e2a4c9019eb53f62790fadf86c14a54f4cf4888), but failed due to
whitespace (?!).
Yes, symptoms would be consistent with deadlock on resume.
And yes, the patch seems to fix problem for me.
Tested-by: Pavel Machek <pa...@ucw.cz>
Pavel
> -------------------------8<-------------------------
>
> diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
> index 9f68d0f306b8..4d6043ee7834 100644
> --- a/drivers/cpufreq/cpufreq.c
> +++ b/drivers/cpufreq/cpufreq.c
> @@ -1109,16 +1109,12 @@ void refresh_frequency_limits(struct cpufreq_policy
> *policy)
> {
> struct cpufreq_policy new_policy;
>
> - down_write(&policy->rwsem);
> -
> if (!policy_is_inactive(policy)) {
> new_policy = *policy;
> pr_debug("updating policy for CPU %u\n", policy->cpu);
>
> cpufreq_set_policy(policy, &new_policy);
> }
> -
> - up_write(&policy->rwsem);
> }
> EXPORT_SYMBOL(refresh_frequency_limits);
>
> @@ -1128,7 +1124,9 @@ static void handle_update(struct work_struct *work)
> container_of(work, struct cpufreq_policy, update);
>
> pr_debug("handle_update for cpu %u called\n", policy->cpu);
> + down_write(&policy->rwsem);
> refresh_frequency_limits(policy);
> + up_write(&policy->rwsem);
> }
>
> -------------------------8<-------------------------
>
> Though it makes me wonder why I didn't hit this thing. I was using the
> cpu_cooling device the other day, which calls cpufreq_update_policy()
> very frequently on heat-up. And I had a hair dryer blowing over my
> board to heat it up. Lemme check that again :)
Can you test on some x86 ACPI? No dryers needed :-).
> @Rafael: You want me to send a new diff patch with Fixes tag this time
> if this works out fine ?
Pavel
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