linux-kernel - [PATCH] regulator: max8907: Fix the usage of uninitialized variable in max8907_regulator

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Date:   Thu,  3 Oct 2019 10:58:13 -0700
From:   Yizhuo <yzhai003@....edu>
To:     unlisted-recipients:; (no To-header on input)
Cc:     csong@...ucr.edu, zhiyunq@...ucr.edu, Yizhuo <yzhai003@....edu>,
        Liam Girdwood <lgirdwood@...il.com>,
        Mark Brown <broonie@...nel.org>, linux-kernel@...r.kernel.org
Subject: [PATCH] regulator: max8907: Fix the usage of uninitialized variable in max8907_regulator_probe()

Inside function max8907_regulator_probe(), variable val could
be uninitialized if regmap_read() fails. However, val is used
later in the if statement to decide the content written to
"pmic", which is potentially unsafe.

Signed-off-by: Yizhuo <yzhai003@....edu>
---
 drivers/regulator/max8907-regulator.c | 15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/drivers/regulator/max8907-regulator.c b/drivers/regulator/max8907-regulator.c
index 76152aaa330b..96dc0eea7659 100644
--- a/drivers/regulator/max8907-regulator.c
+++ b/drivers/regulator/max8907-regulator.c
@@ -296,7 +296,10 @@ static int max8907_regulator_probe(struct platform_device *pdev)
 	memcpy(pmic->desc, max8907_regulators, sizeof(pmic->desc));
 
 	/* Backwards compatibility with MAX8907B; SD1 uses different voltages */
-	regmap_read(max8907->regmap_gen, MAX8907_REG_II2RR, &val);
+	ret = regmap_read(max8907->regmap_gen, MAX8907_REG_II2RR, &val);
+	if (ret)
+		return ret;
+
 	if ((val & MAX8907_II2RR_VERSION_MASK) ==
 	    MAX8907_II2RR_VERSION_REV_B) {
 		pmic->desc[MAX8907_SD1].min_uV = 637500;
@@ -333,14 +336,20 @@ static int max8907_regulator_probe(struct platform_device *pdev)
 		}
 
 		if (pmic->desc[i].ops == &max8907_ldo_ops) {
-			regmap_read(config.regmap, pmic->desc[i].enable_reg,
+			ret = regmap_read(config.regmap, pmic->desc[i].enable_reg,
 				    &val);
+			if (ret)
+				return ret;
+
 			if ((val & MAX8907_MASK_LDO_SEQ) !=
 			    MAX8907_MASK_LDO_SEQ)
 				pmic->desc[i].ops = &max8907_ldo_hwctl_ops;
 		} else if (pmic->desc[i].ops == &max8907_out5v_ops) {
-			regmap_read(config.regmap, pmic->desc[i].enable_reg,
+			ret = regmap_read(config.regmap, pmic->desc[i].enable_reg,
 				    &val);
+			if (ret)
+				return ret;
+
 			if ((val & (MAX8907_MASK_OUT5V_VINEN |
 						MAX8907_MASK_OUT5V_ENSRC)) !=
 			    MAX8907_MASK_OUT5V_ENSRC)
-- 
2.17.1