Re: [igt-dev] [PATCH igt] lib: Use C99 initialisers to clear context parameters

[Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>]

On 07/03/2018 14:40, Chris Wilson wrote:
> Quoting Tvrtko Ursulin (2018-03-07 14:36:34)
>>
>> On 07/03/2018 12:17, Chris Wilson wrote:
>>> valgrind complains we feed uninitialised stack into the CONTEXT_SETPARAM
>>> ioctl. It is unused by the kernel, but valgrind doesn't know that and
>>> it's easy enough to clear the struct to prevent the warning.
>>>
>>> Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
>>> ---
>>>    lib/igt_gt.c | 29 ++++++++++++-----------------
>>>    1 file changed, 12 insertions(+), 17 deletions(-)
>>>
>>> diff --git a/lib/igt_gt.c b/lib/igt_gt.c
>>> index 799ca1ae..168c5a07 100644
>>> --- a/lib/igt_gt.c
>>> +++ b/lib/igt_gt.c
>>> @@ -126,11 +126,10 @@ void igt_require_hang_ring(int fd, int ring)
>>>    
>>>    static unsigned context_get_ban(int fd, unsigned ctx)
>>>    {
>>> -     struct drm_i915_gem_context_param param;
>>> -
>>> -     param.param = I915_CONTEXT_PARAM_BANNABLE;
>>> -     param.value = 0;
>>> -     param.size = 0;
>>> +     struct drm_i915_gem_context_param param = {
>>> +             .ctx_id = ctx,
>>
>> Where was this assignment before? Was it all broken as well as upsetting
>> Valgrind?
> 
> It existed only in the callers imagination. Broken is an
> overstatement, since no one varied from the defaults, i.e. the caller
> has to mix in using PARAM_BANNABLE with igt_hang_ctx.

gem_reset_stats is doing that, both with default and own context. But I 
don't feel like untangling this right now. Whatever it is supposed to 
be, if it breaks, it was broken anyway and not a fault of this patch. so:

Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>

Regards,

Tvrtko

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