[Intel-gfx] [PATCH] drm/i915: Fix possible null ptr dereferences

[Pallavi Mishra]

add null ptr checks to prevent crash/exceptions.

Signed-off-by: Pallavi Mishra <pallavi.mis...@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