Re: build failure of next-20220817 for amdgpu due to 7bc913085765 ("drm/amdkfd: Try to schedule bottom half on same core")

[Felix Kuehling]

On 2022-08-18 15:34, Randy Dunlap wrote:
> Hi--
>
> On 8/18/22 12:15, Sudip Mukherjee wrote:
> > On Thu, Aug 18, 2022 at 4:10 PM Randy Dunlap <rdunlap@xxxxxxxxxxxxx> wrote:
> > > On 8/18/22 03:43, Sudip Mukherjee wrote:
> > > > On Thu, Aug 18, 2022 at 3:09 AM Randy Dunlap <rdunlap@xxxxxxxxxxxxx> wrote:
> > > > > On 8/17/22 19:01, Alex Deucher wrote:
> > > > > > On Wed, Aug 17, 2022 at 6:03 PM Sudip Mukherjee (Codethink)
> > > > > > <sudipm.mukherjee@xxxxxxxxx> wrote:
> > > > > > > Hi All,
> > > > > > >
> > > > > > > Not sure if it has been reported, build of next-20220817 fails with the
> > > > > > > error:
> > > > > > >
> > > > > > > ERROR: modpost: "cpu_smallcore_map" [drivers/gpu/drm/amd/amdgpu/amdgpu.ko] undefined!
> > > > > > >
> > > > > > > Trying to do a git bisect to find out the offending commit.
> > > > > > Thanks.  I don't see that symbol in the driver at all.  Not sure where
> > > > > > it is coming from.
> > > > > It's powerpc only.
> > > > >
> > > > > Sudip, is it non-CONFIG_SMP by any chance?
> > > > Ohhh.. really sorry for the incomplete report. I should not try to
> > > > mail while travelling.
> > > >
> > > > The error is seen with powerpc allmodconfig and it has CONFIG_SMP=y.
> > > OK, I see that also, but it doesn't make any sense (to me).
> > >
> > > I did 'objdump' on the code file (amdgpu.o) and it's listed as
> > > undefined but there are no code references to it.
> > cpu_smt_mask() is called by drivers/gpu/drm/amd/amdkfd/kfd_device.c.
> > and cpu_smt_mask() is an inline function in
> > arch/powerpc/include/asm/smp.h which is doing "return
> > per_cpu(cpu_smallcore_map, cpu);"
> >
> > So, the offending commit is 7bc913085765 ("drm/amdkfd: Try to schedule
> > bottom half on same core").
> Thanks for digging that up.
>
> It just needs to have that symbol exported I think.
> This builds cleanly now.
> I can submit it or one of the AMD gfx developers can do so.

I'm not sure where I would need to submit this. And I'm not familiar 
with Powerpc code at all. I'm OK if you submit this wherever it needs to go.

Thanks,
  Felix


> ---
>   arch/powerpc/kernel/smp.c |    1 +
>   1 file changed, 1 insertion(+)
>
> --- a/arch/powerpc/kernel/smp.c
> +++ b/arch/powerpc/kernel/smp.c
> @@ -86,6 +86,7 @@ DEFINE_PER_CPU(cpumask_var_t, cpu_core_m
>   static DEFINE_PER_CPU(cpumask_var_t, cpu_coregroup_map);
>   
>   EXPORT_PER_CPU_SYMBOL(cpu_sibling_map);
> +EXPORT_PER_CPU_SYMBOL(cpu_smallcore_map);
>   EXPORT_PER_CPU_SYMBOL(cpu_l2_cache_map);
>   EXPORT_PER_CPU_SYMBOL(cpu_core_map);
>   EXPORT_SYMBOL_GPL(has_big_cores);