From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751133AbVIWSk6 (ORCPT ); Fri, 23 Sep 2005 14:40:58 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751135AbVIWSk5 (ORCPT ); Fri, 23 Sep 2005 14:40:57 -0400 Received: from frankvm.xs4all.nl ([80.126.170.174]:59045 "EHLO janus.localdomain") by vger.kernel.org with ESMTP id S1751133AbVIWSk5 (ORCPT ); Fri, 23 Sep 2005 14:40:57 -0400 Date: Fri, 23 Sep 2005 20:40:56 +0200 From: Frank van Maarseveen To: Dipankar Sarma Cc: Frank van Maarseveen , Pablo Fernandez , linux-kernel@vger.kernel.org Subject: Re: max_fd Message-ID: <20050923184056.GA2024@janus> References: <8518592505092305373465a5@mail.gmail.com> <20050923155509.GA4723@in.ibm.com> <20050923170345.GA1555@janus> <20050923172653.GA4573@in.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20050923172653.GA4573@in.ibm.com> User-Agent: Mutt/1.4.1i X-Subliminal-Message: Use Linux! Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Sep 23, 2005 at 10:56:53PM +0530, Dipankar Sarma wrote: > > Well, the main reason is that if that code is somehow copied > by to a lock-free critical section, it could cause problems. > If you dereference ->fdt multiple times in a lock-free > section, you could see two different pointers due to > a concurrent update. thanks for the explanation. This raises a lot of other questions. What if max_fds is updated by RCU right after obtaining it... -- Frank