On 17/08/17 23:07, Ilia Mirkin wrote:
> On Thu, Aug 17, 2017 at 6:03 PM, Colin King <colin.king@xxxxxxxxxxxxx> wrote:
>> From: Colin Ian King <colin.king@xxxxxxxxxxxxx>
>>
>> The null check on the array msto is incorrect since msto is never
>> null. The null check should be instead on msto[i] since this is
>> being dereferenced in the call to drm_mode_connector_attach_encoder.
>>
>> Thanks to Emil Velikov for pointing out the mistake in my original
>> fix and for suggesting the correct fix.
>>
>> Detected by CoverityScan, CID#1375915 ("Array compared against 0")
>>
>> Fixes: f479c0ba4a17 ("drm/nouveau/kms/nv50: initial support for DP 1.2 multi-stream")
>> Signed-off-by: Colin Ian King <colin.king@xxxxxxxxxxxxx>
>> ---
>> drivers/gpu/drm/nouveau/nv50_display.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/gpu/drm/nouveau/nv50_display.c b/drivers/gpu/drm/nouveau/nv50_display.c
>> index f7b4326a4641..ed444ecd9e85 100644
>> --- a/drivers/gpu/drm/nouveau/nv50_display.c
>> +++ b/drivers/gpu/drm/nouveau/nv50_display.c
>> @@ -3141,7 +3141,7 @@ nv50_mstc_new(struct nv50_mstm *mstm, struct drm_dp_mst_port *port,
>> mstc->connector.funcs->reset(&mstc->connector);
>> nouveau_conn_attach_properties(&mstc->connector);
>>
>> - for (i = 0; i < ARRAY_SIZE(mstm->msto) && mstm->msto; i++)
>> + for (i = 0; i < ARRAY_SIZE(mstm->msto) && mstm->msto[i]; i++)
>
> Ben will have to rule on which way is correct, but another
> interpretation is that it should be
>
> for (...; i < ARRAY_SIZE; i++)
> if (mstm->msto[i])
> do_stuff()
Yes, I suspect that is a better generic solution top cope with potential
"holes".
>
> I haven't the faintest clue whether the msto array can have "holes" or not.
Indeed. Let's see what Ben says.
>
>> drm_mode_connector_attach_encoder(&mstc->connector, &mstm->msto[i]->encoder);
>>
>> drm_object_attach_property(&mstc->connector.base, dev->mode_config.path_property, 0);
>> --
>> 2.11.0
>>
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