Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753739Ab3F1S56 (ORCPT ); Fri, 28 Jun 2013 14:57:58 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:41925 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752015Ab3F1S5y (ORCPT ); Fri, 28 Jun 2013 14:57:54 -0400 From: Kamal Mostafa To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: "Michael S. Tsirkin" , Jason Wang , "David S. Miller" , Kamal Mostafa Subject: [PATCH 079/105] tuntap: forbid changing mq flag for persistent device Date: Fri, 28 Jun 2013 11:51:41 -0700 Message-Id: <1372445527-24414-80-git-send-email-kamal@canonical.com> X-Mailer: git-send-email 1.8.1.2 In-Reply-To: <1372445527-24414-1-git-send-email-kamal@canonical.com> References: <1372445527-24414-1-git-send-email-kamal@canonical.com> X-Extended-Stable: 3.8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1857 Lines: 52 3.8.13.4 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Jason Wang [ Upstream commit 8e6d91ae0917bf934ed86411148f79d904728d51 ] We currently allow changing the mq flag (IFF_MULTI_QUEUE) for a persistent device. This will result a mismatch between the number the queues in netdev and tuntap. This is because we only allocate a 1q netdevice when IFF_MULTI_QUEUE was not specified, so when we set the IFF_MULTI_QUEUE and try to attach more queues later, netif_set_real_num_tx_queues() may fail which result a single queue netdevice with multiple sockets attached. Solve this by disallowing changing the mq flag for persistent device. Bug was introduced by commit edfb6a148ce62e5e19354a1dcd9a34e00815c2a1 (tuntap: reduce memory using of queues). Reported-by: Sriram Narasimhan Cc: Michael S. Tsirkin Signed-off-by: Jason Wang Signed-off-by: David S. Miller Signed-off-by: Kamal Mostafa --- drivers/net/tun.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/net/tun.c b/drivers/net/tun.c index 522dc0a..2129cf90 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -1585,6 +1585,10 @@ static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr) else return -EINVAL; + if (!!(ifr->ifr_flags & IFF_MULTI_QUEUE) != + !!(tun->flags & TUN_TAP_MQ)) + return -EINVAL; + if (tun_not_capable(tun)) return -EPERM; err = security_tun_dev_open(tun->security); -- 1.8.1.2 -- 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/