linux-kernel - Re: [PATCH] iio: imu: bmi160: Fix the error handling at bmi160_chip

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Date:   Sat, 14 May 2022 15:36:25 +0100
From:   Jonathan Cameron <jic23@...nel.org>
To:     Zheyu Ma <zheyuma97@...il.com>
Cc:     lars@...afoo.de, andriy.shevchenko@...ux.intel.com,
        sean@...nix.com, linux-iio@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] iio: imu: bmi160: Fix the error handling at
 bmi160_chip_init()

On Fri, 13 May 2022 22:35:13 +0800
Zheyu Ma <zheyuma97@...il.com> wrote:

> When the driver fails in bmi160_chip_init(), it should disable the
> regulator.
> 
> The following log shows it:
> 
> [   18.709662] WARNING: CPU: 0 PID: 294 at drivers/regulator/core.c:2257 _regulator_put+0x3ec/0x4e0
> [   18.712069] RIP: 0010:_regulator_put+0x3ec/0x4e0
> [   18.716395] Call Trace:
> [   18.716522]  <TASK>
> [   18.716636]  regulator_bulk_free+0x82/0xe0
> [   18.717077]  i2c_device_probe+0x6f0/0x800
> 
> Fixes: 5dea3fb066f0 ("iio: imu: bmi160: added regulator support")
> Signed-off-by: Zheyu Ma <zheyuma97@...il.com>

Hi,

Good find, but Tong Zhang got their first and the resulting patch
fixes an additional issue missed in this fix. See below.

Jonathan

> ---
>  drivers/iio/imu/bmi160/bmi160_core.c | 17 +++++++++++------
>  1 file changed, 11 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/iio/imu/bmi160/bmi160_core.c b/drivers/iio/imu/bmi160/bmi160_core.c
> index 824b5124a5f5..33abfc2bbd7c 100644
> --- a/drivers/iio/imu/bmi160/bmi160_core.c
> +++ b/drivers/iio/imu/bmi160/bmi160_core.c
> @@ -730,7 +730,7 @@ static int bmi160_chip_init(struct bmi160_data *data, bool use_spi)
>  
>  	ret = regmap_write(data->regmap, BMI160_REG_CMD, BMI160_CMD_SOFTRESET);
>  	if (ret)
> -		return ret;
> +		goto err_regulator_disable;
>  
>  	usleep_range(BMI160_SOFTRESET_USLEEP, BMI160_SOFTRESET_USLEEP + 1);
>  
> @@ -741,29 +741,34 @@ static int bmi160_chip_init(struct bmi160_data *data, bool use_spi)
>  	if (use_spi) {
>  		ret = regmap_read(data->regmap, BMI160_REG_DUMMY, &val);
>  		if (ret)
> -			return ret;
> +			goto err_regulator_disable;
>  	}
>  
>  	ret = regmap_read(data->regmap, BMI160_REG_CHIP_ID, &val);
>  	if (ret) {
>  		dev_err(dev, "Error reading chip id\n");
> -		return ret;
> +		goto err_regulator_disable;
>  	}
>  	if (val != BMI160_CHIP_ID_VAL) {
>  		dev_err(dev, "Wrong chip id, got %x expected %x\n",
>  			val, BMI160_CHIP_ID_VAL);
> -		return -ENODEV;
> +		ret = -ENODEV;
> +		goto err_regulator_disable;
>  	}
>  
>  	ret = bmi160_set_mode(data, BMI160_ACCEL, true);
>  	if (ret)
> -		return ret;
> +		goto err_regulator_disable;
>  
>  	ret = bmi160_set_mode(data, BMI160_GYRO, true);
>  	if (ret)

A failure here does not disable the accelerometer (which is done
in the uninit() function which we we never end
up running.


> -		return ret;
> +		goto err_regulator_disable;
>  
>  	return 0;
> +
> +err_regulator_disable:
> +	regulator_bulk_disable(ARRAY_SIZE(data->supplies), data->supplies);
> +	return ret;
>  }
>  
>  static int bmi160_data_rdy_trigger_set_state(struct iio_trigger *trig,