Re: [PATCH v2 1/1] ACPI: scan: Use unique number for instance_no

[Rafael J. Wysocki]

On Fri, Mar 19, 2021 at 7:33 PM Andy Shevchenko
<andriy.shevchenko@xxxxxxxxxxxxxxx> wrote:
>
> Current mechanism of incrementing and decrementing plain integer
> to get a next free instance_no when creating an ACPI device is buggy.
>
> The simple integer and operations line increment and decrement
> on top of it can't cover the possible gaps during run time. The
> arbitrary instantiation and elimination of the devices is racy

But it isn't racy AFAICS.  It always happens under acpi_device_lock().

> and after a couple of iterations with unequal amount of devices
> being added and removed we may reproduce a bug: