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);
--
2.21.0.rc0.269.g1a574e7a288b
