Re: [PATCH] drm/msm/dpu: Fix variable dereferenced before check

[Abhinav Kumar]

Copying freedreno

On 6/21/2022 10:42 AM, Abhinav Kumar wrote:
> On 6/21/2022 4:06 AM, sunliming wrote:
> > Fixes the following smatch warning:
> >
> > drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_wb.c:261
> > dpu_encoder_phys_wb_atomic_check() warn: variable dereferenced before 
> > check 'conn_state'
> >
> > Reported-by: kernel test robot <lkp@xxxxxxxxx>
> > Signed-off-by: sunliming <sunliming@xxxxxxxxxx>
> Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
> Reviewed-by: Abhinav Kumar <quic_abhinavk@xxxxxxxxxxx>
>
> > ---
> >   drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_wb.c | 10 +++++-----
> >   1 file changed, 5 insertions(+), 5 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_wb.c 
> > b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_wb.c
> > index 59da348ff339..0ec809ab06e7 100644
> > --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_wb.c
> > +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_wb.c
> > @@ -252,11 +252,6 @@ static int dpu_encoder_phys_wb_atomic_check(
> >       DPU_DEBUG("[atomic_check:%d, \"%s\",%d,%d]\n",
> >               phys_enc->wb_idx, mode->name, mode->hdisplay, 
> > mode->vdisplay);
> > -    if (!conn_state->writeback_job || !conn_state->writeback_job->fb)
> > -        return 0;
> > -
> > -    fb = conn_state->writeback_job->fb;
> > -
> >       if (!conn_state || !conn_state->connector) {
> >           DPU_ERROR("invalid connector state\n");
> >           return -EINVAL;
> > @@ -267,6 +262,11 @@ static int dpu_encoder_phys_wb_atomic_check(
> >           return -EINVAL;
> >       }
> > +    if (!conn_state->writeback_job || !conn_state->writeback_job->fb)
> > +        return 0;
> > +
> > +    fb = conn_state->writeback_job->fb;
> > +
> >       DPU_DEBUG("[fb_id:%u][fb:%u,%u]\n", fb->base.id,
> >               fb->width, fb->height);