From 1d422ecfc48ee683ae1ccc9217764f6310c0ffce Mon Sep 17 00:00:00 2001
From: Yang Yingliang <yangyingliang@huawei.com>
Date: Fri, 8 Oct 2021 14:31:50 +0800
Subject: [PATCH] power: supply: max17040: fix null-ptr-deref in max17040_probe()
Git-commit: 1d422ecfc48ee683ae1ccc9217764f6310c0ffce
Patch-mainline: v5.16-rc1
References: git-fixes stable-5.14.19

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>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/power/supply/max17040_battery.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/power/supply/max17040_battery.c b/drivers/power/supply/max17040_battery.c
index 3cea92e28dc3..a9aef1e8b186 100644
--- 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);
-- 
2.26.2