linux-kernel - [PATCH] regulator: clear state each invocation of of_regulator

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Message-Id: <1359486073-26504-1-git-send-email-swarren@wwwdotorg.org>
Date:	Tue, 29 Jan 2013 12:01:13 -0700
From:	Stephen Warren <swarren@...dotorg.org>
To:	Mark Brown <broonie@...nsource.wolfsonmicro.com>,
	Liam Girdwood <lgirdwood@...il.com>
Cc:	Axel Lin <axel.lin@...ics.com>,
	Graeme Gregory <gg@...mlogic.co.uk>,
	Laxman Dewangan <ldewangan@...dia.com>,
	AnilKumar Ch <anilkumar@...com>, linux-kernel@...r.kernel.org
Subject: [PATCH] regulator: clear state each invocation of of_regulator_match

From: Stephen Warren <swarren@...dia.com>

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.

Cc: stable@...r.kernel.org
Signed-off-by: Stephen Warren <swarren@...dia.com>
---
 drivers/regulator/of_regulator.c |    6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/regulator/of_regulator.c b/drivers/regulator/of_regulator.c
index 6f68491..66ca769 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);
-- 
1.7.10.4

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