list_for_each_entry(ippdrv, &exynos_drm_ippdrv_list, drv_list) {
                DRM_DEBUG_KMS("count[%d]ippdrv[0x%x]\n", count++, (int)ippdrv);
 
-               list_for_each_entry(c_node, &ippdrv->cmd_list, list)
-                       if (c_node->property.prop_id == prop_id)
+               mutex_lock(&ippdrv->cmd_lock);
+               list_for_each_entry(c_node, &ippdrv->cmd_list, list) {
+                       if (c_node->property.prop_id == prop_id) {
+                               mutex_unlock(&ippdrv->cmd_lock);
                                return ippdrv;
+                       }
+               }
+               mutex_unlock(&ippdrv->cmd_lock);
        }
 
        return ERR_PTR(-ENODEV);
        if (!prop_list->ipp_id) {
                list_for_each_entry(ippdrv, &exynos_drm_ippdrv_list, drv_list)
                        count++;
+
                /*
                 * Supports ippdrv list count for user application.
                 * First step user application getting ippdrv count.
         * when we find this command no using prop_id.
         * return property information set in this command node.
         */
+       mutex_lock(&ippdrv->cmd_lock);
        list_for_each_entry(c_node, &ippdrv->cmd_list, list) {
                if ((c_node->property.prop_id == prop_id) &&
                    (c_node->state == IPP_STATE_STOP)) {
+                       mutex_unlock(&ippdrv->cmd_lock);
                        DRM_DEBUG_KMS("found cmd[%d]ippdrv[0x%x]\n",
                                property->cmd, (int)ippdrv);
 
                        return 0;
                }
        }
+       mutex_unlock(&ippdrv->cmd_lock);
 
        DRM_ERROR("failed to search property.\n");
 
 
        INIT_LIST_HEAD(&c_node->event_list);
        list_splice_init(&priv->event_list, &c_node->event_list);
+       mutex_lock(&ippdrv->cmd_lock);
        list_add_tail(&c_node->list, &ippdrv->cmd_list);
+       mutex_unlock(&ippdrv->cmd_lock);
 
        /* make dedicated state without m2m */
        if (!ipp_is_m2m_cmd(property->cmd))
 
                c_node->state = IPP_STATE_STOP;
                ippdrv->dedicated = false;
+               mutex_lock(&ippdrv->cmd_lock);
                ipp_clean_cmd_node(c_node);
 
                if (list_empty(&ippdrv->cmd_list))
                        pm_runtime_put_sync(ippdrv->dev);
+               mutex_unlock(&ippdrv->cmd_lock);
                break;
        case IPP_CTRL_PAUSE:
                cmd_work = c_node->stop_work;
                ippdrv->event_workq = ctx->event_workq;
                ippdrv->sched_event = ipp_sched_event;
                INIT_LIST_HEAD(&ippdrv->cmd_list);
+               mutex_init(&ippdrv->cmd_lock);
 
                if (is_drm_iommu_supported(drm_dev)) {
                        ret = drm_iommu_attach_device(drm_dev, ippdrv->dev);
        DRM_DEBUG_KMS("for priv[0x%x]\n", (int)priv);
 
        list_for_each_entry(ippdrv, &exynos_drm_ippdrv_list, drv_list) {
+               mutex_lock(&ippdrv->cmd_lock);
                list_for_each_entry_safe(c_node, tc_node,
                        &ippdrv->cmd_list, list) {
                        DRM_DEBUG_KMS("count[%d]ippdrv[0x%x]\n",
                                        pm_runtime_put_sync(ippdrv->dev);
                        }
                }
+               mutex_unlock(&ippdrv->cmd_lock);
        }
 
        kfree(priv);
 
  * @event_workq: event work queue.
  * @c_node: current command information.
  * @cmd_list: list head for command information.
+ * @cmd_lock: lock for synchronization of access to cmd_list.
  * @prop_list: property informations of current ipp driver.
  * @check_property: check property about format, size, buffer.
  * @reset: reset ipp block.
        struct workqueue_struct *event_workq;
        struct drm_exynos_ipp_cmd_node *c_node;
        struct list_head        cmd_list;
+       struct mutex    cmd_lock;
        struct drm_exynos_ipp_prop_list prop_list;
 
        int (*check_property)(struct device *dev,