Crash in acpi_ns_validate_handle triggered by soundwire on Linux 5.10

[Pierre-Louis Bossart]

>> Linux 5.10 fails to boot on my IceLake laptop, where 5.9 worked fine.
>> I'm not sure whether it's a bug in ACPI or Soundwire subsystem, so I'm
>> sending this to both
>> lists. The W taint flag is because of an unrelated nouveau failure (It
>> was busted on 5.9, and is
>> still on 5.10). Full kernel log down below.
>> It's from a distro kernel, but I can build my own kernel with patches if needed.
> 
> Please try to add a check for handle against NULL to
> snd_intel_dsp_check_soundwire() after
> 
> handle = ACPI_HANDLE(&pci->dev);
> 
> and see if this makes any difference.
> 
> This should check handle against NULL anyway, even if it didn't crash later on.

Is there a way you can share the DSDT?

The only thing we do in that sdw_intel_acpi_scan() function is check for 
an _ADR and read two _DSD properties. I think it's been 2 years since we 
wrote it and never had an issue, never say never I guess...

If you want to bypass this problem for the time being, you can add a 
kernel option in /etc/modprobe.d/alsa-base.conf

options snd-intel-dspcfg dsp_driver=1

that will force the use of the HDaudio legacy driver and bypass the 
driver autodetection.