Re: [PATCH 1/3] drm/amdgpu: disallow multiple FENCE chunks in one submit

[Alex Deucher]

Applied.  Thanks!

On Thu, Aug 6, 2026 at 8:03 AM Christian König <christian.koenig@xxxxxxx> wrote:
>
> On 8/6/26 06:45, Junrui Luo via B4 Relay wrote:
> > amdgpu_cs_pass1() dispatches on chunk_id once per chunk without
> > rejecting repeated ids. p->uf_bo is a single-slot field, so a
> > submission carrying two AMDGPU_CHUNK_ID_FENCE chunks runs
> > amdgpu_cs_p1_user_fence() twice, and the second run overwrites
> > p->uf_bo with a freshly referenced BO without dropping the reference
> > taken by the first.
> >
> > amdgpu_cs_parser_fini() only unrefs the final p->uf_bo, so every FENCE
> > chunk but the last leaks a BO reference. The leaked BO outlives handle
> > close and process exit.
> >
> > Reject duplicate FENCE chunks the same way commit fec5f8e8c6bc
> > ("drm/amdgpu: disallow multiple BO_HANDLES chunks in one submit") did
> > for p->bo_list.
> >
> > Fixes: d38ceaf99ed0 ("drm/amdgpu: add core driver (v4)")
> > Reported-by: Yuhao Jiang <danisjiang@xxxxxxxxx>
> > Assisted-by: Claude:claude-opus-5
> > Cc: stable@xxxxxxxxxxxxxxx
> > Signed-off-by: Junrui Luo <moonafterrain@xxxxxxxxxxx>
>
> Reviewed-by: Christian König <christian.koenig@xxxxxxx>
>
> Thanks,
> Christian.
>
> > ---
> >  drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c | 4 ++++
> >  1 file changed, 4 insertions(+)
> >
> > diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
> > index 5445f75741b5..9c514cb01096 100644
> > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
> > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
> > @@ -228,6 +228,10 @@ static int amdgpu_cs_pass1(struct amdgpu_cs_parser *p,
> >                         if (size < sizeof(struct drm_amdgpu_cs_chunk_fence))
> >                                 goto free_partial_kdata;
> >
> > +                       /* Only a single user fence is allowed to simplify handling. */
> > +                       if (p->uf_bo)
> > +                               goto free_partial_kdata;
> > +
> >                         ret = amdgpu_cs_p1_user_fence(p, p->chunks[i].kdata,
> >                                                       &uf_offset);
> >                         if (ret)
> >
> > --
> > 2.51.2
> >
> >
>