Re: [PATCH] drm: fix uninitialized acquire_ctx fields

["Ville Syrjälä" <ville.syrjala@linux.intel.com>]

On Sat, Jun 07, 2014 at 08:29:13AM -0400, Rob Clark wrote:
> The acquire ctx will typically be declared on the stack, which means we
> could have garbage values for any uninitialized field.  In this case, it
> was triggering WARN_ON()s because 'contended' had garbage value.
> 
> Go ahead and use memset() to be more future-proof.
> 
> Reported-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
> Signed-off-by: Rob Clark <robdclark@gmail.com>
> ---
>  drivers/gpu/drm/drm_modeset_lock.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/gpu/drm/drm_modeset_lock.c b/drivers/gpu/drm/drm_modeset_lock.c
> index 7c2497d..4e8b244 100644
> --- a/drivers/gpu/drm/drm_modeset_lock.c
> +++ b/drivers/gpu/drm/drm_modeset_lock.c
> @@ -64,6 +64,7 @@
>  void drm_modeset_acquire_init(struct drm_modeset_acquire_ctx *ctx,
>  		uint32_t flags)
>  {
> +	memset(ctx, 0, sizeof(ctx));
                              ^^^
*ctx

with that fixed:
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Tested-by: Ville Syrjälä <ville.syrjala@linux.intel.com>

>  	ww_acquire_init(&ctx->ww_ctx, &crtc_ww_class);
>  	INIT_LIST_HEAD(&ctx->locked);
>  }
> -- 
> 1.9.3

-- 
Ville Syrjälä
Intel OTC