Re: [PATCH] cpufreq: scpi/scmi: Fix freeing of dynamic OPPs

From: Valentin Schneider
Date: Fri Jan 04 2019 - 05:40:14 EST


On 04/01/2019 09:44, Viresh Kumar wrote:
> Since the commit 2a4eb7358aba ("OPP: Don't remove dynamic OPPs from
> _dev_pm_opp_remove_table()"), dynamically created OPP aren't
> automatically removed anymore by dev_pm_opp_cpumask_remove_table(). This
> affects the scpi and scmi cpufreq drivers which no longer free OPPs on
> failures or on invocations of the policy->exit() callback.
> Create a generic OPP helper dev_pm_opp_remove_all_dynamic() which can be
> called from these drivers instead of dev_pm_opp_cpumask_remove_table().
> In dev_pm_opp_remove_all_dynamic(), we need to make sure that the
> opp_list isn't getting accessed simultaneously from other parts of the
> OPP core while the helper is freeing dynamic OPPs, i.e. we can't drop
> the opp_table->lock while traversing through the OPP list. And to
> accomplish that, this patch also creates _opp_kref_release_unlocked()
> which can be called from this new helper with the opp_table lock already
> held.
> Cc: 4.20 <stable@xxxxxxxxxxxxxxx> # v4.20
> Reported-by: Valentin Schneider <valentin.schneider@xxxxxxx>
> Fixes: 2a4eb7358aba ("OPP: Don't remove dynamic OPPs from _dev_pm_opp_remove_table()")
> Signed-off-by: Viresh Kumar <viresh.kumar@xxxxxxxxxx>

Gave it a spin on my Juno, and I don't see the refcount warning anymore so:

Tested-by: Valentin Schneider <valentin.schneider@xxxxxxx>

Thanks for having a look at this.