linux-kernel - ACPI fan driver: uninitialized variable when CONFIG

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Date:	Mon, 29 Apr 2013 05:32:11 -0700
From:	Michel Lespinasse <walken@...gle.com>
To:	Zhang Rui <rui.zhang@...el.com>
Cc:	linux-acpi@...r.kernel.org, LKML <linux-kernel@...r.kernel.org>
Subject: ACPI fan driver: uninitialized variable when CONFIG_PM is not set

In the following code:

static int fan_get_cur_state(struct thermal_cooling_device *cdev, unsigned long
                             *state)
{
        struct acpi_device *device = cdev->devdata;
        int result;
        int acpi_state;

        if (!device)
                return -EINVAL;

        result = acpi_bus_update_power(device->handle, &acpi_state);
        if (result)
                return result;

        *state = (acpi_state == ACPI_STATE_D3 ? 0 :
                 (acpi_state == ACPI_STATE_D0 ? 1 : -1));
        return 0;
}

With CONFIG_PM not set, acpi_bus_update_power() returns 0 and does not
initialize acpi_state. This results in acpi_state being used before
initialization.

(I found out by random chance, as I suppose people don't normally
build without CONFIG_PM anymore ?)

I'm not sure what a proper fix would be, so I'll just report this here
and enable CONFIG_PM locally :)

-- 
Michel "Walken" Lespinasse
A program is never fully debugged until the last user dies.
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