linux-kernel - Re: [PATCH] hwmon: sht3x: initialize variable 'ret' in update_interval

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Message-ID: <e2ae44a3-b3c8-4f90-a180-c619e1854317@roeck-us.net>
Date: Sun, 12 Oct 2025 11:07:23 -0700
From: Guenter Roeck <linux@...ck-us.net>
To: Ranganath V N <vnranganath.20@...il.com>
Cc: Jean Delvare <jdelvare@...e.com>, linux-hwmon@...r.kernel.org,
	linux-kernel@...r.kernel.org, skhan@...uxfoundation.org,
	david.hunter.linux@...il.com, khalid@...nel.org,
	linux-kernel-mentees@...ts.linuxfoundation.org
Subject: Re: [PATCH] hwmon: sht3x: initialize variable 'ret' in
 update_interval_write().

On Sun, Oct 12, 2025 at 05:13:27PM +0530, Ranganath V N wrote:
> fix for the smatch errors:
> drivers/hwmon/sht3x.c:606 update_interval_write() error: uninitialized symbol 'ret'.
> 
> The warning can occur when both the data->mode and mode which is
> derived from get_mode_from_update_interval() are zero.
> In this case, no i2c command is sent and ret remains undefined
> before reaching the coman return path.
> 
> When both data->mode and mode are zero, the device remains in
> single shot mode and no configuration change is required.
> In such cases, it is correct to treat the operation as successful
> without issuing any i2c transfer.

Actually, in this case, the code enters

       if (mode == data->mode) {
                mutex_unlock(&data->data_lock);
                return 0;
        }

meaning the problem does not actually exist because 'ret' will be
initialized if either 'mode' or 'data->mode' is != 0. That means
the smatch report is a false positive, and this patch is not required.

Guenter