From patchwork Thu Nov 28 12:48:09 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Wei Liu X-Patchwork-Id: 294874 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 18A0D2C008A for ; Thu, 28 Nov 2013 23:48:17 +1100 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754857Ab3K1MsM (ORCPT ); Thu, 28 Nov 2013 07:48:12 -0500 Received: from smtp.citrix.com ([66.165.176.89]:33729 "EHLO SMTP.CITRIX.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750841Ab3K1MsL (ORCPT ); Thu, 28 Nov 2013 07:48:11 -0500 X-IronPort-AV: E=Sophos;i="4.93,790,1378857600"; d="scan'208";a="78968211" Received: from accessns.citrite.net (HELO FTLPEX01CL02.citrite.net) ([10.9.154.239]) by FTLPIPO01.CITRIX.COM with ESMTP; 28 Nov 2013 12:48:10 +0000 Received: from ukmail1.uk.xensource.com (10.80.16.128) by smtprelay.citrix.com (10.13.107.79) with Microsoft SMTP Server id 14.2.342.4; Thu, 28 Nov 2013 07:48:10 -0500 Received: from dt47.uk.xensource.com ([10.80.229.47] helo=dt47.uk.xensource.com.) by ukmail1.uk.xensource.com with esmtp (Exim 4.69) (envelope-from ) id 1Vm10r-0004GH-St; Thu, 28 Nov 2013 12:48:09 +0000 From: Wei Liu To: , , CC: , Wei Liu , Ian Campbell , Konrad Wilk , David Vrabel Subject: [[PATCH stable <3.12]] xen-netback: fix refcnt unbalance for 3.11 and earlier versions Date: Thu, 28 Nov 2013 12:48:09 +0000 Message-ID: <1385642889-11513-1-git-send-email-wei.liu2@citrix.com> X-Mailer: git-send-email 1.7.10.4 MIME-Version: 1.0 X-DLP: MIA1 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org 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 verion reference counting code was not correctly modified, and the reset of vif->tx_irq was lost. If frontend goes through vif life cycle more than once the reference counting is skewed. This patch adds back the missing tx_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. 3.12 and onward versions are not affected by this bug, because reference counting code was removed due to the introduction of 1:1 model. This pacth should be backported to all stable verions which are lower than 3.12 and have 279f438e36. Reported-and-tested-by: Tomasz Wroblewski Signed-off-by: Wei Liu Cc: Ian Campbell Cc: Konrad Wilk Cc: David Vrabel Acked-by: Ian Campbell --- drivers/net/xen-netback/interface.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/drivers/net/xen-netback/interface.c b/drivers/net/xen-netback/interface.c index d28324a..342d4e5 100644 --- a/drivers/net/xen-netback/interface.c +++ b/drivers/net/xen-netback/interface.c @@ -418,9 +418,6 @@ 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->tx_irq) { if (vif->tx_irq == vif->rx_irq) unbind_from_irqhandler(vif->tx_irq, vif); @@ -428,6 +425,7 @@ void xenvif_disconnect(struct xenvif *vif) unbind_from_irqhandler(vif->tx_irq, vif); unbind_from_irqhandler(vif->rx_irq, vif); } + vif->tx_irq = 0; } xen_netbk_unmap_frontend_rings(vif); @@ -435,6 +433,9 @@ void xenvif_disconnect(struct xenvif *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);