Re: [PATCH] usb: typec: ucsi: acpi: don't dereference a missing ACPI companion

[Huang Wei]

Hi Yogesh,

I checked this over. The fix is correct - the sysfs bind path can
indeed hand a non-ACPI platform device to ucsi_acpi_probe(), and
adev->dep_unmet is the first dereference.

I also went and checked the "only unchecked ACPI_COMPANION() in
drivers/usb/typec" claim. port-mapper.c looked like a second candidate
at first glance, but typec_link_ports() bails out early when the port
has no ACPI companion, so typec_port_match() never runs with
con_adev == NULL. The claim holds.

Fixes: 1f3546ff3f0a is also the right one for the stable backport -
that commit added the dep_unmet check back in 2020, so the deref has
been there a while.

Reviewed-by: Huang Wei <huangwei@xxxxxxxxxx>

Thanks,
Huang Wei