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

[Greg Kroah-Hartman]

On Mon, Sep 21, 2026 at 11:03:46AM +0800, Huang Wei wrote:
> 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.

And that's the problem, don't do that.  Seriously, if userspace does it,
it deserves the pieces the kernel ends up in.  This isn't a kernel
issue, it's a userspace "do not do this" issue.

There is now a taint flag that gets set if userspace tries to do this,
showing us all what is really going on, so we can ignore reports like
this.  Also syzbot now should not be attempting foolish things like
this.

thanks,

greg k-h