Re: [PATCH] drm/i915: In render_state_init reset obj in teardown path

Dave Gordon
2016-04-26T10:04:11Z

On 26/04/16 10:21, Matthew Auld wrote:
> The teardown path in render_state_init leaves so->obj != NULL.
>
> Suggested-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
> Signed-off-by: Matthew Auld <matthew.auld@intel.com>
> ---
> drivers/gpu/drm/i915/i915_gem_render_state.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/drivers/gpu/drm/i915/i915_gem_render_state.c b/drivers/gpu/drm/i915/i915_gem_render_state.c
> index 71611bf..10f3cf0 100644
> --- a/drivers/gpu/drm/i915/i915_gem_render_state.c
> +++ b/drivers/gpu/drm/i915/i915_gem_render_state.c
> @@ -70,6 +70,7 @@ static int render_state_init(struct render_state *so, struct drm_device *dev)
>
> free_gem:
> drm_gem_object_unreference(&so->obj->base);
> + so->obj = NULL;
> return ret;
> }

It doesn't actually matter, because 'so' is pointing to a local object a
few frames up the callstack. But I don't think this function is entitled
to assume that; it should leave everything in a consistent state so
there aren't any dangling pointers to objects that have been freed lying
around - someday the argument may turn into a per-engine static or some
other long-lived thing. So,

Reviewed-by: Dave Gordon <david.s.gordon@intel.com>