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

[Andy Shevchenko]

On Fri, Mar 19, 2021 at 07:51:00PM +0100, Rafael J. Wysocki wrote:
> 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().

Hmm.. indeed. I sent a v3 with the commit message based on your proposal.


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

-- 
With Best Regards,
Andy Shevchenko