On Thu, Oct 1, 2026 at 12:56 PM Linus Walleij <[email protected]> wrote:
> On Mon, Sep 28, 2026 at 9:22 AM Bill Wendling <[email protected]> wrote:
> > On Sun, Sep 27, 2026 at 11:38 PM Bill Wendling <[email protected]> wrote:
> > >
> > > The 'data' pointer field in 'struct acpi_gpio_mapping' is associated
> > > with the 'size' field, which represents the number of elements of
> > > type 'struct acpi_gpio_params' allocated for 'data'.
> > >
> > > To improve bounds checking via CONFIG_UBSAN_BOUNDS and
> > > CONFIG_FORTIFY_SOURCE, annotate 'data' with the __counted_by_ptr
> > > attribute.
> > >
> > > Analysis of allocation, assignment, and access points shows that the
> > > pointer is never accessed before the count is set, which guarantees that
> > > this annotation is safe and will not cause runtime panics or
> > > false-positive bounds checks.
> > >
> > > Cc: [email protected]
> > > Assisted-by: LLM
> > > Signed-off-by: Bill Wendling <[email protected]>
> > > ---
> > > include/linux/gpio/consumer.h | 2 +-
> > > 1 file changed, 1 insertion(+), 1 deletion(-)
> > >
> > > diff --git a/include/linux/gpio/consumer.h b/include/linux/gpio/consumer.h
> > > index fceeefd5f893..2b80cf7aa7e7 100644
> > > --- a/include/linux/gpio/consumer.h
> > > +++ b/include/linux/gpio/consumer.h
> > > @@ -667,7 +667,7 @@ struct acpi_gpio_params {
> > >
> > > struct acpi_gpio_mapping {
> > > const char *name;
> > > - const struct acpi_gpio_params *data;
> > > + const struct acpi_gpio_params *data __counted_by_ptr(size);
> > > unsigned int size;
> > >
> > > /* Ignore IoRestriction field */
> >
> > There's a problem with 'drivers/firmware/efi/libstub/Makefile'. Clang
> > needs a compiler flag to support the "__counted_by_ptr" attribute
> > referencing a field *after* the pointer, like in this patch. However,
> > the Makefile blasts the flag away for x86 platforms. Below is a hack
> > that copies the part of the top-level Makefile that adds the flag. I
> > don't think that's a good solution. The comment in the driver's
> > Makefile says that the stub code executes before the kernel does,
> > which I assume is why a lot of the flags are blown away... In any
> > event, I'm not sure how best to address this.
>
> But is this a problem with the current patch?
>
> Does libefistub use <linux/gpio/consumer.h> in any way, shape
> or form?
>
It's being #included transitively:
In file included from drivers/firmware/efi/libstub/efi-stub-helper.c:12:
In file included from ./include/linux/efi.h:20:
In file included from ./include/linux/rtc.h:18:
In file included from ./include/linux/nvmem-provider.h:16:
./include/linux/gpio/consumer.h:670:55: error: use of undeclared
identifier 'size'; did you
mean 'ksize'?
670 | const struct acpi_gpio_params *data __counted_by_ptr(size);
| ^~~~
| ksize
././include/linux/compiler_types.h:392:64: note: expanded from macro
'__counted_by_ptr'
392 | #define __counted_by_ptr(member)
__attribute__((__counted_by__(member)))
|
^~~~~~
./include/linux/slab.h:602:8: note: 'ksize' declared here
602 | size_t ksize(const void *objp);
| ^
> Yours,
> Linus Walleij
