From: Viresh Kumar Date: Fri, 18 Oct 2019 08:41:58 +0000 (+0530) Subject: opp: Reinitialize the list_kref before adding the static OPPs again X-Git-Tag: v5.4-rc5~28^2^3^2 X-Git-Url: https://repo.jachan.dev/linux.git/commitdiff_plain/b19c23551be8de0d4e59fe6af70f10763e3cc595 opp: Reinitialize the list_kref before adding the static OPPs again 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 Tested-by: Dmitry Osipenko Signed-off-by: Viresh Kumar --- 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);