regulator: clear state each invocation of of_regulator_match

of_regulator_match() saves some dynamcially allocated state into the
match table that's passed to it. By implementation and not contract, for
each match table entry, if non-NULL state is already present,
of_regulator_match() will not overwrite it. of_regulator_match() is
typically called each time a regulator is probe()d. This means it is
called with the same match table over and over again if a regulator
triggers deferred probe. This results in stale, kfree()d data being left
in the match table from probe to probe, which causes a variety of crashes
or use of invalid data.

Explicitly free all output state from of_regulator_match() before
generating new results in order to avoid this.

Signed-off-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Cc: stable@vger.kernel.org

diff --git a/drivers/regulator/of_regulator.c b/drivers/regulator/of_regulator.c
index 6f68491..66ca769 100644 (file)
--- a/drivers/regulator/of_regulator.c
+++ b/drivers/regulator/of_regulator.c
@@ -120,6 +120,12 @@ int of_regulator_match(struct device *dev, struct device_node *node,
        if (!dev || !node)
                return -EINVAL;
 
+       for (i = 0; i < num_matches; i++) {
+               struct of_regulator_match *match = &matches[i];
+               match->init_data = NULL;
+               match->of_node = NULL;
+       }
+
        for_each_child_of_node(node, child) {
                name = of_get_property(child,
                                        "regulator-compatible", NULL);