Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753305AbaAMQBW (ORCPT ); Mon, 13 Jan 2014 11:01:22 -0500 Received: from youngberry.canonical.com ([91.189.89.112]:52846 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753227AbaAMQBP (ORCPT ); Mon, 13 Jan 2014 11:01:15 -0500 From: Luis Henriques To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Wei Liu , Ian Campbell , Konrad Wilk , David Vrabel , Luis Henriques Subject: [PATCH 3.11 013/208] xen-netback: fix refcnt unbalance for 3.11 and earlier versions Date: Mon, 13 Jan 2014 15:57:34 +0000 Message-Id: <1389628849-1614-14-git-send-email-luis.henriques@canonical.com> X-Mailer: git-send-email 1.8.3.2 In-Reply-To: <1389628849-1614-1-git-send-email-luis.henriques@canonical.com> References: <1389628849-1614-1-git-send-email-luis.henriques@canonical.com> X-Extended-Stable: 3.11 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.11.10.3 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Wei Liu 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 Signed-off-by: Luis Henriques --- 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); -- 1.8.3.2 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/