[Intel-gfx] [PATCH v2] drm/i915: Use GEM_BUG_ON for obj ptr NULL check

[Pallavi Mishra]

add GEM_BUG_ON to check for NULL ptr dereferences with
obj ptr, this will help catch exceptions in CI tests.

v2 change commit text

Signed-off-by: Pallavi Mishra <pallavi.mishra at intel.com>
---
 drivers/gpu/drm/i915/gem/i915_gem_ttm.c      | 3 +++
 drivers/gpu/drm/i915/gem/i915_gem_ttm_move.c | 3 ++-
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_ttm.c b/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
index 218a9b3037c7..997fe73c205b 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
@@ -906,6 +906,8 @@ vm_access_ttm(struct vm_area_struct *area, unsigned long addr,
 	struct drm_i915_gem_object *obj =
 		i915_ttm_to_gem(area->vm_private_data);
 
+	GEM_BUG_ON(!obj);
+
 	if (i915_gem_object_is_readonly(obj) && write)
 		return -EACCES;
 
@@ -966,6 +968,7 @@ static const struct drm_i915_gem_object_ops i915_gem_ttm_obj_ops = {
 void i915_ttm_bo_destroy(struct ttm_buffer_object *bo)
 {
 	struct drm_i915_gem_object *obj = i915_ttm_to_gem(bo);
+	GEM_BUG_ON(!obj);
 
 	i915_gem_object_release_memory_region(obj);
 	mutex_destroy(&obj->ttm.get_io_page.lock);
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_ttm_move.c b/drivers/gpu/drm/i915/gem/i915_gem_ttm_move.c
index 80df9f592407..2b684903a9f5 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_ttm_move.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_ttm_move.c
@@ -371,6 +371,7 @@ int i915_ttm_move_notify(struct ttm_buffer_object *bo)
 	struct drm_i915_gem_object *obj = i915_ttm_to_gem(bo);
 	int ret;
 
+	GEM_BUG_ON(!obj);
 	ret = i915_gem_object_unbind(obj, I915_GEM_OBJECT_UNBIND_ACTIVE);
 	if (ret)
 		return ret;
@@ -506,7 +507,7 @@ static void i915_ttm_memcpy_init(struct i915_ttm_memcpy_arg *arg,
 
 	dst_reg = i915_ttm_region(bo->bdev, dst_mem->mem_type);
 	src_reg = i915_ttm_region(bo->bdev, bo->resource->mem_type);
-	GEM_BUG_ON(!dst_reg || !src_reg);
+	GEM_BUG_ON(!dst_reg || !src_reg || !obj);
 
 	arg->dst_iter = !i915_ttm_cpu_maps_iomem(dst_mem) ?
 		ttm_kmap_iter_tt_init(&arg->_dst_iter.tt, dst_ttm) :
-- 
2.25.1