From patchwork Mon Dec 2 17:49:54 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Wei Liu X-Patchwork-Id: 295972 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id D2D592C00A4 for ; Tue, 3 Dec 2013 04:50:13 +1100 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753203Ab3LBRuE (ORCPT ); Mon, 2 Dec 2013 12:50:04 -0500 Received: from smtp.citrix.com ([66.165.176.89]:5344 "EHLO SMTP.CITRIX.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753178Ab3LBRtz (ORCPT ); Mon, 2 Dec 2013 12:49:55 -0500 X-IronPort-AV: E=Sophos;i="4.93,812,1378857600"; d="scan'208";a="79797019" Received: from accessns.citrite.net (HELO FTLPEX01CL01.citrite.net) ([10.9.154.239]) by FTLPIPO01.CITRIX.COM with ESMTP; 02 Dec 2013 17:49:54 +0000 Received: from ukmail1.uk.xensource.com (10.80.16.128) by smtprelay.citrix.com (10.13.107.78) with Microsoft SMTP Server id 14.2.342.4; Mon, 2 Dec 2013 12:49:54 -0500 Received: from zion.uk.xensource.com ([10.80.2.73]) by ukmail1.uk.xensource.com with esmtp (Exim 4.69) (envelope-from ) id 1VnXd4-0002vH-3Y; Mon, 02 Dec 2013 17:49:54 +0000 Date: Mon, 2 Dec 2013 17:49:54 +0000 From: Wei Liu To: Greg KH CC: Wei Liu , , , , , Ian Campbell , Konrad Wilk , David Vrabel Subject: Re: [[PATCH stable <3.12]] xen-netback: fix refcnt unbalance for 3.11 and earlier versions Message-ID: <20131202174954.GD14293@zion.uk.xensource.com> References: <1385642889-11513-1-git-send-email-wei.liu2@citrix.com> <20131201044835.GB19516@kroah.com> <20131202120134.GA14293@zion.uk.xensource.com> <20131202171958.GA661@kroah.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20131202171958.GA661@kroah.com> User-Agent: Mutt/1.5.21 (2010-09-15) X-DLP: MIA1 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Mon, Dec 02, 2013 at 09:19:58AM -0800, Greg KH wrote: [...] > As 3.11.y is now dead, there's not much I can do with that one, but I > could use a backport for 3.10.y, as this patch does not apply there, > thanks. > Here it is. ---8<--- From f92adc90042cb725cf6351141f52e9fc71639a89 Mon Sep 17 00:00:00 2001 From: Wei Liu Date: Mon, 2 Dec 2013 17:44:09 +0000 Subject: [PATCH] xen-netback: fix refcnt unbalance for 3.10 With the introduction of "xen-netback: Don't destroy the netdev until the vif is shut down" (upstream commit id 279f438e36), vif disconnect and free are separated. However in the backported version reference counting code was not correctly modified, and the reset of vif->irq was lost. If frontend goes through vif life cycle more than once the reference counting is skewed. This patch adds back the missing vif->irq reset line. It also moves several lines of the reference counting code to vif_free, so the moved code corresponds to the counterpart in vif_alloc, thus the reference counting is balanced. Signed-off-by: Wei Liu Acked-by: Ian Campbell Cc: Konrad Wilk Cc: David Vrabel --- drivers/net/xen-netback/interface.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/drivers/net/xen-netback/interface.c b/drivers/net/xen-netback/interface.c index c4a2eb2..540a796 100644 --- a/drivers/net/xen-netback/interface.c +++ b/drivers/net/xen-netback/interface.c @@ -365,17 +365,19 @@ void xenvif_disconnect(struct xenvif *vif) if (netif_carrier_ok(vif->dev)) xenvif_carrier_off(vif); - atomic_dec(&vif->refcnt); - wait_event(vif->waiting_to_free, atomic_read(&vif->refcnt) == 0); - - if (vif->irq) + if (vif->irq) { unbind_from_irqhandler(vif->irq, vif); + vif->irq = 0; + } xen_netbk_unmap_frontend_rings(vif); } void xenvif_free(struct xenvif *vif) { + atomic_dec(&vif->refcnt); + wait_event(vif->waiting_to_free, atomic_read(&vif->refcnt) == 0); + unregister_netdev(vif->dev); free_netdev(vif->dev);