Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934058AbcLIQSO (ORCPT ); Fri, 9 Dec 2016 11:18:14 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:55320 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933447AbcLIQSM (ORCPT ); Fri, 9 Dec 2016 11:18:12 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Eric Dumazet , Jason Wang , "Michael S. Tsirkin" , "David S. Miller" Subject: [PATCH 4.4 01/28] virtio-net: add a missing synchronize_net() Date: Fri, 9 Dec 2016 17:17:43 +0100 Message-Id: <20161209161747.977767448@linuxfoundation.org> X-Mailer: git-send-email 2.10.2 In-Reply-To: <20161209161747.923205441@linuxfoundation.org> References: <20161209161747.923205441@linuxfoundation.org> User-Agent: quilt/0.65 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1162 Lines: 40 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Eric Dumazet [ Upstream commit 963abe5c8a0273a1cf5913556da1b1189de0e57a ] It seems many drivers do not respect napi_hash_del() contract. When napi_hash_del() is used before netif_napi_del(), an RCU grace period is needed before freeing NAPI object. Fixes: 91815639d880 ("virtio-net: rx busy polling support") Signed-off-by: Eric Dumazet Cc: Jason Wang Cc: Michael S. Tsirkin Acked-by: Michael S. Tsirkin Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- drivers/net/virtio_net.c | 5 +++++ 1 file changed, 5 insertions(+) --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -1465,6 +1465,11 @@ static void virtnet_free_queues(struct v netif_napi_del(&vi->rq[i].napi); } + /* We called napi_hash_del() before netif_napi_del(), + * we need to respect an RCU grace period before freeing vi->rq + */ + synchronize_net(); + kfree(vi->rq); kfree(vi->sq); }