On 18-10-19, 18:35, Dmitry Osipenko wrote:
> 18.10.2019 12:28, Viresh Kumar пишет:
> > The list_kref reaches a count of 0 when all the static OPPs are removed,
> > for example when dev_pm_opp_of_cpumask_remove_table() is called, though
> > the actual OPP table may not get freed as it may still be referenced by
> > other parts of the kernel, like from a call to
> > dev_pm_opp_set_supported_hw(). And if we call
> > dev_pm_opp_of_cpumask_add_table() again at this point, we must
> > reinitialize the list_kref otherwise the kernel will hit a WARN() in
> > kref infrastructure for incrementing a kref with value 0.
> >
> > Fixes: 11e1a1648298 ("opp: Don't decrement uninitialized list_kref")
> > Reported-by: Dmitry Osipenko <[email protected]>
> > Signed-off-by: Viresh Kumar <[email protected]>
> > ---
> > drivers/opp/of.c | 7 +++++++
> > 1 file changed, 7 insertions(+)
> >
> > diff --git a/drivers/opp/of.c b/drivers/opp/of.c
> > index 6dc41faf74b5..1cbb58240b80 100644
> > --- a/drivers/opp/of.c
> > +++ b/drivers/opp/of.c
> > @@ -663,6 +663,13 @@ static int _of_add_opp_table_v2(struct device *dev,
> > struct opp_table *opp_table)
> > return 0;
> > }
> >
> > + /*
> > + * Re-initialize list_kref every time we add static OPPs to the OPP
> > + * table as the reference count may be 0 after the last tie static OPPs
> > + * were removed.
> > + */
> > + kref_init(&opp_table->list_kref);
> > +
> > /* We have opp-table node now, iterate over it and add OPPs */
> > for_each_available_child_of_node(opp_table->np, np) {
> > opp = _opp_add_static_v2(opp_table, dev, np);
> >
>
> I don't see the warning anymore, cpufreq-dt module reloading works fine
> now. Thank you very much!
>
> Tested-by: Dmitry Osipenko <[email protected]>
Thanks for testing.
--
viresh
