From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751541AbbEATSl (ORCPT ); Fri, 1 May 2015 15:18:41 -0400 Received: from mx1.redhat.com ([209.132.183.28]:37418 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751307AbbEATSh (ORCPT ); Fri, 1 May 2015 15:18:37 -0400 Message-ID: <5543D184.4070707@redhat.com> Date: Fri, 01 May 2015 15:18:28 -0400 From: Rik van Riel User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.4.0 MIME-Version: 1.0 To: "Paul E. McKenney" , Linux kernel Mailing List Subject: RCU recursion? (code inspection) Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Paul, While looking at synchronize_rcu(), I noticed that synchronize_rcu_expedited() calls synchronize_sched_expedited(), which can call synchronize_sched() when it is worried about the counter wrapping, which can call synchronize_sched_expedited() The code is sufficiently convoluted that I am unsure whether this recursion can actually happen in practice, but I also did not spot anything that would stop it. -- All rights reversed