Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752734Ab3IILPY (ORCPT ); Mon, 9 Sep 2013 07:15:24 -0400 Received: from merlin.infradead.org ([205.233.59.134]:48238 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752415Ab3IILPW (ORCPT ); Mon, 9 Sep 2013 07:15:22 -0400 Date: Mon, 9 Sep 2013 13:15:08 +0200 From: Peter Zijlstra To: Lei Wen Cc: Ingo Molnar , mingo@redhat.com, leiwen@marvell.com, linux-kernel@vger.kernel.org Subject: Re: Question regarding list_for_each_entry_safe usage in move_one_task Message-ID: <20130909111508.GO31370@twins.programming.kicks-ass.net> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2012-12-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 696 Lines: 17 On Mon, Sep 02, 2013 at 02:26:45PM +0800, Lei Wen wrote: > Hi Peter, > > I find one list API usage may not be correct in current fair.c code. > In move_one_task function, it may iterate through whole cfs_tasks > list to get one task to move. > > But in dequeue_task(), it would delete one task node from list > without the lock protection. So that we could see from > list_for_each_entry_safe API definitoin: Both sites hold the required rq->lock. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/