From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Lively Subject: ignoring xenbus state transitions during shutdown Date: Mon, 25 Jun 2007 14:41:30 -0400 Message-ID: <46800C5A.2050201@virtualiron.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: xen-devel@lists.xensource.com List-Id: xen-devel@lists.xenproject.org Hi Folks - In otherend_changed() in xenbus_probe.c, the driver is trying to ignore xenbus state transitions while the guest OS is shutting down. It currently does this by looking for system_state > SYSTEM_RUNNING. But system_state is not exported by some kernels that use it (e.g., SLES9 running in a HVM guest), so the xenbus driver can't be loaded. The comments indicate we're trying to avoid a failure that occurs when there is no rootfs. I haven't yet seen this failure (after removing the code my shutdowns with PV drivers seemed to work fine, though I haven't pushed hard yet), but I suspect I shouldn't be ignoring it. I was thinking it might be better to test for the screw condition (no rootfs) directly, perhaps something like try vfs_stat("/", &stat) and see whether it fails (??). (These state transitions are relatively rare, so it doesn't need to be a particularly cheap test.) Any other suggestions? I've heard of the old global 'system_running', but that's not used SLES9, at least. Thanks in Advance, Dave