Re: [PATCH][drm-next] drm/i915/gvt: ensure -ve return value is handled correctly

[Zhenyu Wang]

On 2017.09.19 19:35:23 -0700, Joe Perches wrote:
> On Wed, 2017-09-20 at 05:46 +0800, Zhenyu Wang wrote:
> > On 2017.09.19 16:55:34 +0100, Colin King wrote:
> > > From: Colin Ian King <colin.king@xxxxxxxxxxxxx>
> > > 
> > > An earlier fix changed the return type from find_bb_size however the
> > > integer return is being assigned to a unsigned int so the -ve error
> > > check will never be detected. Make bb_size an int to fix this.
> > > 
> > > Detected by CoverityScan CID#1456886 ("Unsigned compared against 0")
> > > 
> > > Fixes: 1e3197d6ad73 ("drm/i915/gvt: Refine error handling for perform_bb_shadow")
> > > Signed-off-by: Colin Ian King <colin.king@xxxxxxxxxxxxx>
> > > ---
> > >  drivers/gpu/drm/i915/gvt/cmd_parser.c | 2 +-
> > >  1 file changed, 1 insertion(+), 1 deletion(-)
> > > 
> > > diff --git a/drivers/gpu/drm/i915/gvt/cmd_parser.c b/drivers/gpu/drm/i915/gvt/cmd_parser.c
> > > index 2c0ccbb817dc..f41cbf664b69 100644
> > > --- a/drivers/gpu/drm/i915/gvt/cmd_parser.c
> > > +++ b/drivers/gpu/drm/i915/gvt/cmd_parser.c
> > > @@ -1628,7 +1628,7 @@ static int perform_bb_shadow(struct parser_exec_state *s)
> > >  	struct intel_shadow_bb_entry *entry_obj;
> > >  	struct intel_vgpu *vgpu = s->vgpu;
> > >  	unsigned long gma = 0;
> > > -	uint32_t bb_size;
> > > +	int bb_size;
> > >  	void *dst = NULL;
> > >  	int ret = 0;
> > >  
> > 
> > Applied this, thanks!
> 
> Is it possible for bb_size to be both >= 2g and valid?

Never be possible in practise and if really that big I think something
is already insane indeed.

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