Re: [PATCH RESEND v2 2/5] hwmon: (pmbus/adm1266) add clear_blackbox debugfs entry

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [High] The debugfs write handler `adm1266_clear_blackbox_write` performs an I2C transaction without acquiring the required hardware monitoring locks, violating hwmon subsystem guidelines.
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commit ab9c19373562d58415e28511b037545cfd278c2a
Author: Abdurrahman Hussain <abdurrahman@nexthop.ai>
Subject: hwmon: (pmbus/adm1266) add clear_blackbox debugfs entry

This commit adds a debugfs entry to clear the ADM1266 blackbox buffer by
issuing a block-write command to the device. This is needed when the
device operates in single-recording mode to preserve fault history.

> diff --git a/drivers/hwmon/pmbus/adm1266.c b/drivers/hwmon/pmbus/adm1266.c
> index 7b8433226176f..31aefa8fc75f5 100644
> --- a/drivers/hwmon/pmbus/adm1266.c
> +++ b/drivers/hwmon/pmbus/adm1266.c

[ ... ]

> +static ssize_t adm1266_clear_blackbox_write(struct file *file, const char __user *ubuf,
> +					    size_t count, loff_t *ppos)
> +{
> +	struct i2c_client *client = file->private_data;
> +	u8 payload[2] = { 0xFE, 0x00 };
> +	int ret;
> +
> +	ret = i2c_smbus_write_block_data(client, ADM1266_READ_BLACKBOX,
> +					 sizeof(payload), payload);

Does this I2C block write need to be protected by hwmon_lock() and
hwmon_unlock()?

The hardware monitoring subsystem guidelines require drivers to implement
locking for attributes registered outside of the core registration functions,
such as debugfs entries.

Without these locks, could this write operation race with other multi-record
transactions? For example, if this clear command is interleaved while
adm1266_nvmem_read_blackbox() is iterating through multiple records, might
it corrupt the read sequence?

> +	if (ret < 0)
> +		return ret;
> +
> +	return count;
> +}

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Sashiko AI review · https://sashiko.dev/#/patchset/20260511-adm1266-v2-0-7a6d34f0de5d@nexthop.ai?part=2