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

1 files changed, 6 insertions, 0 deletions

diff --git a/drivers/regulator/of_regulator.c b/drivers/regulator/of_regulator.c
index 6f684916fd79..66ca769287ab 100644
--- 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);