Crash in acpi_ns_validate_handle triggered by soundwire on Linux 5.10

[Marcin Ślusarz]

pt., 29 sty 2021 o 19:59 Marcin Ślusarz <marcin.slusarz at gmail.com> napisał(a):
>
> czw., 28 sty 2021 o 15:32 Marcin Ślusarz <marcin.slusarz at gmail.com> napisał(a):
> >
> > czw., 28 sty 2021 o 13:39 Rafael J. Wysocki <rafael at kernel.org> napisał(a):
> > > The only explanation for that I can think about (and which does not
> > > involve supernatural intervention so to speak) is a stack corruption
> > > occurring between these two calls in sdw_intel_acpi_cb().  IOW,
> > > something scribbles on the handle in the meantime, but ATM I have no
> > > idea what that can be.
> >
> > I tried KASAN but it didn't find anything and kernel actually booted
> > successfully.
>
> I investigated this and it looks like a compiler bug (or something nastier),
> but I can't find where exactly registers get corrupted because if I add printks
> the corruption seems on the printk side, but if I don't add them it seems
> the value gets corrupted earlier.
(...)
> I'm using gcc 10.2.1 from Debian testing.

Someone on IRC, after hearing only that "gcc miscompiles the kernel",
suggested disabling CONFIG_STACKPROTECTOR_STRONG.
It helped indeed and it matches my observations, so it's quite likely it
is the culprit.

What do we do now?

Marcin