[PATCH] regulator: da9121: Fix uninit-value in da9121_assign_chip_model()

[Wei Yongjun <weiyongjun1@huawei.com>]

KASAN report slab-out-of-bounds in __regmap_init as follows:

BUG: KASAN: slab-out-of-bounds in __regmap_init drivers/base/regmap/regmap.c:841
Read of size 1 at addr ffff88803678cdf1 by task xrun/9137

CPU: 0 PID: 9137 Comm: xrun Tainted: G        W         5.18.0-rc2
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x15a lib/dump_stack.c:88
 print_report.cold+0xcd/0x69b mm/kasan/report.c:313
 kasan_report+0x8e/0xc0 mm/kasan/report.c:491
 __regmap_init+0x4540/0x4ba0 drivers/base/regmap/regmap.c:841
 __devm_regmap_init+0x7a/0x100 drivers/base/regmap/regmap.c:1266
 __devm_regmap_init_i2c+0x65/0x80 drivers/base/regmap/regmap-i2c.c:394
 da9121_i2c_probe+0x386/0x6d1 drivers/regulator/da9121-regulator.c:1039
 i2c_device_probe+0x959/0xac0 drivers/i2c/i2c-core-base.c:563

This happend when da9121 device is probe by da9121_i2c_id, but with
invalid dts. Thus, chip->subvariant_id is set to -EINVAL, and later
da9121_assign_chip_model() will access 'regmap' without init it.

Fix it by return -EINVAL from da9121_assign_chip_model() if
'chip->subvariant_id' is invalid.

Fixes: f3fbd5566f6a ("regulator: da9121: Add device variants")
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
---
 drivers/regulator/da9121-regulator.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/regulator/da9121-regulator.c b/drivers/regulator/da9121-regulator.c
index eb9df485bd8a..76e0e23bf598 100644
--- a/drivers/regulator/da9121-regulator.c
+++ b/drivers/regulator/da9121-regulator.c
@@ -1030,6 +1030,8 @@ static int da9121_assign_chip_model(struct i2c_client *i2c,
 		chip->variant_id = DA9121_TYPE_DA9142;
 		regmap = &da9121_2ch_regmap_config;
 		break;
+	default:
+		return -EINVAL;
 	}
 
 	/* Set these up for of_regulator_match call which may want .of_map_modes */
-- 
2.25.1