msm: camera: reqmgr: Avoid freeing subdev twice

The 'l_device' pointer in __cam_req_mgr_destroy_subdev is
set to NULL after freeing but this is done on a
local copy of the variable in stack. This results in
double-free when this function is called again. To avoid
this, pass 'l_device' pointer by reference and assign it
to NULL after freeing.

CRs-Fixed: 3120468
Change-Id: If2dde6f1c702bee26a3c8a68c2f45bafbf0f7cd6
Signed-off-by: Nirmal Abraham <[email protected]>

drivers/cam_req_mgr/cam_req_mgr_core.c

@@ -2347,10 +2347,13 @@ static int __cam_req_mgr_create_subdevs(
  *
  */
 static void __cam_req_mgr_destroy_subdev(
-	struct cam_req_mgr_connected_device *l_device)
+	struct cam_req_mgr_connected_device **l_device)
 {
-	kfree(l_device);
-	l_device = NULL;
+	CAM_DBG(CAM_CRM, "*l_device %pK", *l_device);
+	if (*(l_device) != NULL) {
+		kfree(*(l_device));
+		*l_device = NULL;
+	}
 }
 
 /**
@@ -3982,7 +3985,7 @@ static int __cam_req_mgr_unlink(
 	__cam_req_mgr_destroy_link_info(link);
 	/* Free memory holding data of linked devs */
 
-	__cam_req_mgr_destroy_subdev(link->l_dev);
+	__cam_req_mgr_destroy_subdev(&link->l_dev);
 
 	/* Destroy the link handle */
 	rc = cam_destroy_device_hdl(link->link_hdl);
@@ -4162,7 +4165,7 @@ int cam_req_mgr_link(struct cam_req_mgr_ver_info *link_info)
 	mutex_unlock(&g_crm_core_dev->crm_lock);
 	return rc;
 setup_failed:
-	__cam_req_mgr_destroy_subdev(link->l_dev);
+	__cam_req_mgr_destroy_subdev(&link->l_dev);
 create_subdev_failed:
 	cam_destroy_device_hdl(link->link_hdl);
 	link_info->u.link_info_v1.link_hdl = -1;
@@ -4280,7 +4283,7 @@ int cam_req_mgr_link_v2(struct cam_req_mgr_ver_info *link_info)
 	mutex_unlock(&g_crm_core_dev->crm_lock);
 	return rc;
 setup_failed:
-	__cam_req_mgr_destroy_subdev(link->l_dev);
+	__cam_req_mgr_destroy_subdev(&link->l_dev);
 create_subdev_failed:
 	cam_destroy_device_hdl(link->link_hdl);
 	link_info->u.link_info_v2.link_hdl = -1;