The check before alone is not enough for a case where there is another
bug introduced so that
context->stream_count is not in sync with actual number of streams
across entire resource_context.
At least assert indeed should be there.
Andrey
On 03/12/2018 07:06 PM, Li, Roman wrote:
> There is a check just before for-loop that should ensure pipe_ctx is not null:
>
> /* Only supports single display */
> if (context->stream_count != 1)
> return false;
>
> To remove the subject warning - we can rather add an assert:
> assert(pipe_ctx);
>
> Thanks,
> Roman
>
> -----Original Message-----
> From: Grodzovsky, Andrey
> Sent: Monday, March 12, 2018 6:23 PM
> To: David Binderman <dcb314 at hotmail.com>; Deucher, Alexander <Alexander.Deucher at amd.com>; Koenig, Christian <Christian.Koenig at amd.com>; Zhou, David(ChunMing) <David1.Zhou at amd.com>; airlied at linux.ie; amd-gfx at lists.freedesktop.org; dri-devel at lists.freedesktop.org; linux-kernel at vger.kernel.org; Wentland, Harry <Harry.Wentland at amd.com>; Li, Roman <Roman.Li at amd.com>
> Subject: Re: linux-4.16-rc5/drivers/gpu/drm/amd/display/dc/dce110/dce110_hw_sequencer.c:1723]: (warning) Possible null pointer dereference: pipe_ctx
>
>
>
> On 03/12/2018 06:22 AM, David Binderman wrote:
>> hello there,
>>
>> Source code is
>>
>>
>> Â Â Â for (i = 0; i < dc->res_pool->pipe_count; i++) {
>> Â Â Â Â Â Â Â if (res_ctx->pipe_ctx[i].stream) {
>> Â Â Â Â Â Â Â Â Â Â Â pipe_ctx = &res_ctx->pipe_ctx[i];
>> Â Â Â Â Â Â Â Â Â Â Â *pipe_idx = i;
>> Â Â Â Â Â Â Â Â Â Â Â break;
>> Â Â Â Â Â Â Â }
>> Â Â Â }
> Indeed something like
>
> if (!pipe_ctx)
> Â Â Â Â Â Â Â Â Â Â Â Â Â return false;
>
> seems the right thing here.
>
> Harry, Roman , your opinion ?
>
> Andrey
>
>> Â Â Â /* Only supports eDP */
>> Â Â Â if (pipe_ctx->stream->sink->link->connector_signal !=
>> SIGNAL_TYPE_EDP)
>> Â Â Â Â Â Â Â return false;
>>
>> Suggest add some code to deal with the case that the for loop doesn't
>> find what it is looking for and so pipe_ctx is NULL.
>>
>> Regards
>>
>> David Binderman
>>
>> _______________________________________________
>> amd-gfx mailing list
>> amd-gfx at lists.freedesktop.org
>> https://lists.freedesktop.org/mailman/listinfo/amd-gfx
