From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759560Ab3B1Oy4 (ORCPT ); Thu, 28 Feb 2013 09:54:56 -0500 Received: from youngberry.canonical.com ([91.189.89.112]:42542 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933104Ab3B1OvK (ORCPT ); Thu, 28 Feb 2013 09:51:10 -0500 From: Luis Henriques To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: David Vrabel , "David S. Miller" , Luis Henriques Subject: [PATCH 128/139] xen-netback: cancel the credit timer when taking the vif down Date: Thu, 28 Feb 2013 14:44:38 +0000 Message-Id: <1362062689-2567-129-git-send-email-luis.henriques@canonical.com> X-Mailer: git-send-email 1.8.1.2 In-Reply-To: <1362062689-2567-1-git-send-email-luis.henriques@canonical.com> References: <1362062689-2567-1-git-send-email-luis.henriques@canonical.com> X-Extended-Stable: 3.5 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.5.7.7 -stable review patch. If anyone has any objections, please let me know. ------------------ From: David Vrabel commit 3e55f8b306cf305832a4ac78aa82e1b40e818ece upstream. If the credit timer is left armed after calling xen_netbk_remove_xenvif(), then it may fire and attempt to schedule the vif which will then oops as vif->netbk == NULL. This may happen both in the fatal error path and during normal disconnection from the front end. The sequencing during shutdown is critical to ensure that: a) vif->netbk doesn't become unexpectedly NULL; and b) the net device/vif is not freed. 1. Mark as unschedulable (netif_carrier_off()). 2. Synchronously cancel the timer. 3. Remove the vif from the schedule list. 4. Remove it from it netback thread group. 5. Wait for vif->refcnt to become 0. Signed-off-by: David Vrabel Acked-by: Ian Campbell Reported-by: Christopher S. Aker Signed-off-by: David S. Miller Signed-off-by: Luis Henriques --- drivers/net/xen-netback/interface.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/drivers/net/xen-netback/interface.c b/drivers/net/xen-netback/interface.c index b8c5193..221f426 100644 --- a/drivers/net/xen-netback/interface.c +++ b/drivers/net/xen-netback/interface.c @@ -132,6 +132,7 @@ static void xenvif_up(struct xenvif *vif) static void xenvif_down(struct xenvif *vif) { disable_irq(vif->irq); + del_timer_sync(&vif->credit_timeout); xen_netbk_deschedule_xenvif(vif); xen_netbk_remove_xenvif(vif); } @@ -363,8 +364,6 @@ void xenvif_disconnect(struct xenvif *vif) atomic_dec(&vif->refcnt); wait_event(vif->waiting_to_free, atomic_read(&vif->refcnt) == 0); - del_timer_sync(&vif->credit_timeout); - if (vif->irq) unbind_from_irqhandler(vif->irq, vif); -- 1.8.1.2