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Subject[PATCH] power: supply: max17042_battery: fix some usage of uninitialized variables
Date
Several functions in this file are trying to use regmap_read() to
initialize the specific variable, however, if regmap_read() fails,
the variable could be uninitialized but used directly, which is
potentially unsafe. The return value of regmap_read() should be
checked and handled. The same case also happens in function
max17042_thread_handler() but it needs more effort to patch.

Signed-off-by: Yizhuo <yzhai003@ucr.edu>
---
drivers/power/supply/max17042_battery.c | 23 +++++++++++++++++++----
1 file changed, 19 insertions(+), 4 deletions(-)

diff --git a/drivers/power/supply/max17042_battery.c b/drivers/power/supply/max17042_battery.c
index e6a2dacaa730..8e5727010ed2 100644
--- a/drivers/power/supply/max17042_battery.c
+++ b/drivers/power/supply/max17042_battery.c
@@ -675,8 +675,12 @@ static void max17042_reset_vfsoc0_reg(struct max17042_chip *chip)
{
unsigned int vfSoc;
struct regmap *map = chip->regmap;
+ int ret;
+
+ ret = regmap_read(map, MAX17042_VFSOC, &vfSoc);
+ if (ret)
+ return;

- regmap_read(map, MAX17042_VFSOC, &vfSoc);
regmap_write(map, MAX17042_VFSOC0Enable, VFSOC0_UNLOCK);
max17042_write_verify_reg(map, MAX17042_VFSOC0, vfSoc);
regmap_write(map, MAX17042_VFSOC0Enable, VFSOC0_LOCK);
@@ -686,12 +690,18 @@ static void max17042_load_new_capacity_params(struct max17042_chip *chip)
{
u32 full_cap0, rep_cap, dq_acc, vfSoc;
u32 rem_cap;
+ int ret;

struct max17042_config_data *config = chip->pdata->config_data;
struct regmap *map = chip->regmap;

- regmap_read(map, MAX17042_FullCAP0, &full_cap0);
- regmap_read(map, MAX17042_VFSOC, &vfSoc);
+ ret = regmap_read(map, MAX17042_FullCAP0, &full_cap0);
+ if (ret)
+ return ret;
+
+ ret = regmap_read(map, MAX17042_VFSOC, &vfSoc);
+ if (ret)
+ return ret;

/* fg_vfSoc needs to shifted by 8 bits to get the
* perc in 1% accuracy, to get the right rem_cap multiply
@@ -1108,7 +1118,12 @@ static int max17042_probe(struct i2c_client *client,
if (!client->irq)
regmap_write(chip->regmap, MAX17042_SALRT_Th, 0xff00);

- regmap_read(chip->regmap, MAX17042_STATUS, &val);
+ ret = regmap_read(chip->regmap, MAX17042_STATUS, &val);
+ if (ret) {
+ dev_err(&client->dev, "Failed to get MAX17042_STATUS.\n");
+ return ret;
+ }
+
if (val & STATUS_POR_BIT) {
INIT_WORK(&chip->work, max17042_init_worker);
ret = devm_add_action(&client->dev, max17042_stop_work, chip);
--
2.17.1
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