[PATCH v2] drm/msm/dpu: Fix uninitialized variable

[Dmitry Baryshkov]

On Tue, Feb 11, 2025 at 10:23:54AM +0100, Marijn Suijten wrote:
> On 2025-02-10 14:14:14, Abhinav Kumar wrote:
> > 
> > 
> > On 2/9/2025 7:51 PM, Ethan Carter Edwards wrote:
> > > There is a possibility for an uninitialized *ret* variable to be
> > > returned in some code paths.
> > > 
> > > Fix this by initializing *ret* to 0.
> > > 
> > > Addresses-Coverity-ID: 1642546 ("Uninitialized scalar variable")
> > > Fixes: 774bcfb731765d ("drm/msm/dpu: add support for virtual planes")
> > > Signed-off-by: Ethan Carter Edwards <ethan at ethancedwards.com>
> > > ---
> > > Changes in v2:
> > > - Return explicit 0 when no error occurs
> > > - Add hardening mailing lists
> > > - Link to v1: https://lore.kernel.org/r/20250209-dpu-v1-1-0db666884f70@ethancedwards.com
> > > ---
> > >   drivers/gpu/drm/msm/disp/dpu1/dpu_plane.c | 7 +++----
> > >   1 file changed, 3 insertions(+), 4 deletions(-)
> > > 
> > 
> > Thanks for your patch, this was addressed with
> > 
> > https://patchwork.freedesktop.org/patch/631567/ but since this is better 
> > I am fine with this, will pick this one up
> 
> The `return 0;` in this patch should certainly fix this issue entirely and we
> don't need to inline the `int ret` for that, which I think is against mixed
> declaration rules anyway?
> 
> As far as I understand that's what Dmitry suggested in v1, but he r-b'd it in
> this form.  Dmitry, was that intended?

I think it should be fine, if the gcc doesn't warn against it.

> 
> - Marijn
> 
> > Reviewed-by: Abhinav Kumar <quic_abhinavk at quicinc.com>
> > 
> > 
> > > diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_plane.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_plane.c
> > > index 098abc2c0003cde90ce6219c97ee18fa055a92a5..af3e541f60c303eb5212524e877129359b5ca98c 100644
> > > --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_plane.c
> > > +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_plane.c
> > > @@ -1164,7 +1164,6 @@ int dpu_assign_plane_resources(struct dpu_global_state *global_state,
> > >   			       unsigned int num_planes)
> > >   {
> > >   	unsigned int i;
> > > -	int ret;
> > >   
> > >   	for (i = 0; i < num_planes; i++) {
> > >   		struct drm_plane_state *plane_state = states[i];
> > > @@ -1173,13 +1172,13 @@ int dpu_assign_plane_resources(struct dpu_global_state *global_state,
> > >   		    !plane_state->visible)
> > >   			continue;
> > >   
> > > -		ret = dpu_plane_virtual_assign_resources(crtc, global_state,
> > > +		int ret = dpu_plane_virtual_assign_resources(crtc, global_state,
> > >   							 state, plane_state);
> > >   		if (ret)
> > > -			break;
> > > +			return ret;
> > >   	}
> > >   
> > > -	return ret;
> > > +	return 0;
> > >   }
> > >   
> > >   static void dpu_plane_flush_csc(struct dpu_plane *pdpu, struct dpu_sw_pipe *pipe)
> > > 
> > > ---
> > > base-commit: a64dcfb451e254085a7daee5fe51bf22959d52d3
> > > change-id: 20250209-dpu-c3fac78fc617
> > > 
> > > Best regards,
> > 

-- 
With best wishes
Dmitry