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: