linux-kernel - Re: [RFC PATCH v1] platform/x86: wmi: Do not register driver with invalid GUID

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Date:   Fri, 28 Jul 2023 14:39:07 +0000
From:   Barnabás Pőcze <pobrn@...tonmail.com>
To:     Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Cc:     Hans de Goede <hdegoede@...hat.com>, linux-kernel@...r.kernel.org,
        platform-driver-x86@...r.kernel.org,
        Mark Gross <markgross@...nel.org>, Armin Wolf <W_Armin@....de>
Subject: Re: [RFC PATCH v1] platform/x86: wmi: Do not register driver with invalid GUID

Hi


2023. július 28., péntek 12:02 keltezéssel, Andy Shevchenko <andriy.shevchenko@...ux.intel.com> írta:

> On Thu, Jul 27, 2023 at 10:54:26PM +0000, Barnabás Pőcze wrote:
> > 2023. július 26., szerda 10:45 keltezéssel, Hans de Goede <hdegoede@...hat.com> írta:
> > > On 7/15/23 23:24, Barnabás Pőcze wrote:
> 
> ...
> 
> > > I think that having an additional check like the one which you
> > > propose has some value too, even if it is just to cover drivers
> > > which for some reason don't use `MODULE_DEVICE_TABLE()`, but IMHO
> > > the most important check to have is a check in file2alias.c .
> >
> > Okay... any tips on how to avoid copying `uuid_is_valid()`?
> 
> I think I already told the rough design: we need to split uuid.c to three
> files: libuuid.h, libuuid.c uuid.c and libuuid.c should be built twice:
> once for uuid.c and once for file2alias.c. libuuid.h should contain the
> definitions file2alias.c is using.  Something like that.

What is not clear at all to me is how includes should be handled. `uuid_is_valid()`
uses `isxdigit()`, which is found in different header files based on whether it is
a kernel or user space build.


> 
> > Another idea I had was that maybe `struct wmi_device_id::guid_string` needs to be
> > changed to be `guid_t` and then `GUID_INIT()` or something similar could be used
> > to initialize it. That way it is impossible to mess up the format. The only downside
> > I can see is that guid is no longer "grep-able".
> 
> Strictly speaking you may not do that because it's a (semi-)ABI.

Why is that the case?


Regards,
Barnabás Pőcze