Re: Re: [PATCH] usb: typec: ucsi: acpi: Check ACPI companion before use

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

On Tue, Oct 20, 2026 at 10:31:58AM +0800, jiale yao wrote:
> Hi Huang,
> 
> At 2026-10-20 10:27:07, "Huang Wei" <huangwei@kylinos.cn> wrote:
> >Hi Jiale,
> >
> >A heads-up on the history here: a functionally identical patch was
> >posted in September by Yogesh Gaur:
> >
> >  https://lore.kernel.org/linux-usb/20260920090711.300-1-yogeshgaur.83@gmail.com/
> >
> >Greg declined it on the grounds that the only realistic way to reach
> >probe without an ACPI companion is the driver_override + sysfs bind
> >path, which is a deliberate root action, with the resulting OOPS
> >being identifiable by the taint flag - "if userspace does it, it
> >deserves the pieces the kernel ends up in":
> >
> >  https://lore.kernel.org/linux-usb/2026092130-thong-secrecy-1dd4@gregkh/
> >
> >The open question left from that thread was whether syzbot still
> >exercises the override+bind path - if it does and keeps generating
> >these reports, that would be an argument for taking the guard anyway.
> >Yogesh's version referenced a syzbot report; yours does not, so I
> >can't tell from the patch whether you hit the same report or found
> >this independently.
> 
> Thanks for your reply.
> The bug was found by my static analysis tool, which is currently under development.

And how does that tool reach this patch without hitting the "the kernel
is now tainted because the user did something wrong" setting?

thanks,

greg k-h