power: supply: max17040: fix null-ptr-deref in max17040_probe()

[ Upstream commit 1d422ecfc48ee683ae1ccc9217764f6310c0ffce ]

Add check the return value of devm_regmap_init_i2c(), otherwise
later access may cause null-ptr-deref as follows:

KASAN: null-ptr-deref in range [0x0000000000000360-0x0000000000000367]
RIP: 0010:regmap_read+0x33/0x170
Call Trace:
  max17040_probe+0x61b/0xff0 [max17040_battery]
 ? write_comp_data+0x2a/0x90
 ? max17040_set_property+0x1d0/0x1d0 [max17040_battery]
 ? tracer_hardirqs_on+0x33/0x520
 ? __sanitizer_cov_trace_pc+0x1d/0x50
 ? _raw_spin_unlock_irqrestore+0x4b/0x60
 ? trace_hardirqs_on+0x63/0x2d0
 ? write_comp_data+0x2a/0x90
 ? __sanitizer_cov_trace_pc+0x1d/0x50
 ? max17040_set_property+0x1d0/0x1d0 [max17040_battery]
 i2c_device_probe+0xa31/0xbe0

Fixes: 6455a8a84bdf ("power: supply: max17040: Use regmap i2c")
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/power/supply/max17040_battery.c b/drivers/power/supply/max17040_battery.c
index 3cea92e..a9aef1e 100644 (file)
--- a/drivers/power/supply/max17040_battery.c
+++ b/drivers/power/supply/max17040_battery.c
@@ -449,6 +449,8 @@ static int max17040_probe(struct i2c_client *client,
 
        chip->client = client;
        chip->regmap = devm_regmap_init_i2c(client, &max17040_regmap);
+       if (IS_ERR(chip->regmap))
+               return PTR_ERR(chip->regmap);
        chip_id = (enum chip_id) id->driver_data;
        if (client->dev.of_node) {
                ret = max17040_get_of_data(chip);