From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ewan Mellor Subject: Re: [PATCH] fix for bug#515 Date: Fri, 24 Mar 2006 13:40:09 +0000 Message-ID: <20060324134008.GC8825@leeni.uk.xensource.com> References: <1143205525.7690.2.camel@localhost.localdomain> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <1143205525.7690.2.camel@localhost.localdomain> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: Harry Butterworth Cc: xen-devel@lists.xensource.com List-Id: xen-devel@lists.xenproject.org On Fri, Mar 24, 2006 at 01:05:24PM +0000, Harry Butterworth wrote: > # HG changeset patch > # User harry@localhost.localdomain > # Node ID 78704d769fb2f758bc9c05b0911081375fae018d > # Parent 8c21c8ea5fff320d1cc4abd18d11c648cdca322e > Fix bug 515 by adding a global lock around the hotplug scripts in the > non-udev hotplug case only. > > There are two possible root causes for 515, both of which are only > problems in the non-udev hotplug case because udev uses udevsend which > already implements the required serialisation. > > 1) Script concurrency. > 2) Kernel reordering hotplug events. > > This changeset fixes (1) but not (2). Since (1) is the problem that > seems to be happening this is probably OK. > > A fix for (2) for the hotplug case might be to add extra serialisation > using state changes in the store but this would impact all the drivers > and the code and extra complexity would be redundant once everyone had > moved to udev. This doesn't seem worthwhile unless we actually start to > see (2) happening. Applied, thanks Harry. Ewan.