[bug report] drm/ttm: fix re-init of global structures

[Dan Carpenter]

Hello Christian König,

The patch bd4264112f93: "drm/ttm: fix re-init of global structures"
from Apr 16, 2019, leads to the following static checker warning:

	drivers/gpu/drm/ttm/ttm_bo.c:1610 ttm_bo_global_release()
	warn: passing freed memory 'glob'

drivers/gpu/drm/ttm/ttm_bo.c
  1591  static void ttm_bo_global_kobj_release(struct kobject *kobj)
  1592  {
  1593          struct ttm_bo_global *glob =
  1594                  container_of(kobj, struct ttm_bo_global, kobj);
  1595  
  1596          __free_page(glob->dummy_read_page);
  1597  }
  1598  
  1599  static void ttm_bo_global_release(void)
  1600  {
  1601          struct ttm_bo_global *glob = &ttm_bo_glob;
  1602  
  1603          mutex_lock(&ttm_global_mutex);
  1604          if (--ttm_bo_glob_use_count > 0)
  1605                  goto out;
  1606  
  1607          kobject_del(&glob->kobj);
  1608          kobject_put(&glob->kobj);
  1609          ttm_mem_global_release(&ttm_mem_glob);
  1610          memset(glob, 0, sizeof(*glob));
                       ^^^^^^^^^^^^^^^^^^^^^^
Depending on the config kobject_release() might call ttm_bo_global_kobj_release()
a few seconds after this memset.  Maybe put the memset into
ttm_bo_global_kobj_release()?

  1611  out:
  1612          mutex_unlock(&ttm_global_mutex);
  1613  }


regards,
dan carpenter