Re: [PATCH v3 1/3] drm/amd/display: Add ASSERT_BUG() macro definition

[Tiezhu Yang]

On 01/14/2025 04:29 PM, Huacai Chen wrote:
> Hi, Tiezhu,
>
> On Tue, Jan 14, 2025 at 2:16 PM Tiezhu Yang <yangtiezhu@xxxxxxxxxxx> wrote:
> > In order to keep the current ability for the aim of debugging and avoid
> > printing the warning message twice, add ASSERT_BUG() macro definition to
> > harden the callers of division functions.
> >
> > Signed-off-by: Tiezhu Yang <yangtiezhu@xxxxxxxxxxx>
> > ---
> >  drivers/gpu/drm/amd/display/dc/os_types.h | 5 +++++
> >  1 file changed, 5 insertions(+)
> >
> > diff --git a/drivers/gpu/drm/amd/display/dc/os_types.h b/drivers/gpu/drm/amd/display/dc/os_types.h
> > index f2ba76c1e0c0..932bbe05ee0a 100644
> > --- a/drivers/gpu/drm/amd/display/dc/os_types.h
> > +++ b/drivers/gpu/drm/amd/display/dc/os_types.h
> > @@ -79,6 +79,11 @@
> >                         dc_breakpoint();        \
> >         } while (0)
> >
> > +#define ASSERT_BUG(expr) do {                  \
> > +               dc_breakpoint();                \
> > +               BUG_ON(!(expr));                \
> > +       } while (0)
> I don't think this is correct, if KGDB is enabled, then whether expr
> is true or false, ASSERT_BUG() will break to KGDB.

It should check expr first, something like this:

#define ASSERT_BUG(expr) do {                   \
                if (!(expr)) {                  \
                        dc_breakpoint();        \
                        BUG();                  \
                }                               \
        } while (0)

I will send v4 later.

Thanks,
Tiezhu