On Wed, Jul 31, 2019 at 10:48:38AM +0200, Linus Walleij wrote:
> On Tue, Jul 30, 2019 at 3:41 PM Mark Brown <broonie@kernel.org> wrote:

> > Today's -next fails to boot on QDF2400 systems:

> Is this a devicetree or ACPI system? Which devicetree in that case?
> If it is ACPI I assume one had to look into DSDTs?

You can see from the linked logs it's an ACPI system, the ACPI code
announces it during boot.

> Aha. I think this only worked out of chance before.

> What the Qualcomm driver does is exploit that .init_valid_mask() gets called
> even if .need_valid_mask in gpio_chip is not set to true,
> and this is why the bug appears in
> msm_gpio_init_valid_mask(), I'm pretty much sure it is the
> bitmap_zero(chip->valid_mask, max_gpios);
> call towards the end of the function that gets turned
> into:
> 08:56:36.114798  [    4.433713]  __memset+0x80/0x188

> And this causes the crash.

Should init_valid_mask() be being called if need_valid_mask() is false?

> Apparently this only happens on ACPI systems because I tested it
> myself on a DT system.

Might also depend on the particular DT the system has?

> So if OF and ACPI is activated at the same time (can that happen?)

Not really.  There is a stub DT used to pass ACPI to the kernel.