From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id F304DCCA47B for ; Tue, 5 Jul 2022 12:00:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232917AbiGEMAx (ORCPT ); Tue, 5 Jul 2022 08:00:53 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42220 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232882AbiGEMAW (ORCPT ); Tue, 5 Jul 2022 08:00:22 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EE69718358; Tue, 5 Jul 2022 05:00:16 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 868ACB817DA; Tue, 5 Jul 2022 12:00:15 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id F193AC385A2; Tue, 5 Jul 2022 12:00:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1657022414; bh=v40g/hBBeQmr4W1jpD2WWBoeCsbWUBpQuUMf2B4Nk+o=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=wgidaf9VJ7+W87LqiftK2vUYNb3Pe+UD1ANiDnN3VQGbeUpvfjRi344FMtjbLps4t 8iIYDBcH5HNJRSjit4XQehiueaEithfTXUpqyggdiqnQ4Zu1Bb8echq/qm5bJ8X/8n w6k5zUDRjGI+HQrPwjwnQUOxzWjpIJeyBXI8zTMY= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jason Wang , "Michael S. Tsirkin" Subject: [PATCH 4.9 08/29] caif_virtio: fix race between virtio_device_ready() and ndo_open() Date: Tue, 5 Jul 2022 13:57:49 +0200 Message-Id: <20220705115605.993354698@linuxfoundation.org> X-Mailer: git-send-email 2.37.0 In-Reply-To: <20220705115605.742248854@linuxfoundation.org> References: <20220705115605.742248854@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Jason Wang commit 11a37eb66812ce6a06b79223ad530eb0e1d7294d upstream. We currently depend on probe() calling virtio_device_ready() - which happens after netdev registration. Since ndo_open() can be called immediately after register_netdev, this means there exists a race between ndo_open() and virtio_device_ready(): the driver may start to use the device (e.g. TX) before DRIVER_OK which violates the spec. Fix this by switching to use register_netdevice() and protect the virtio_device_ready() with rtnl_lock() to make sure ndo_open() can only be called after virtio_device_ready(). Fixes: 0d2e1a2926b18 ("caif_virtio: Introduce caif over virtio") Signed-off-by: Jason Wang Message-Id: <20220620051115.3142-3-jasowang@redhat.com> Signed-off-by: Michael S. Tsirkin Signed-off-by: Greg Kroah-Hartman --- drivers/net/caif/caif_virtio.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) --- a/drivers/net/caif/caif_virtio.c +++ b/drivers/net/caif/caif_virtio.c @@ -727,13 +727,21 @@ static int cfv_probe(struct virtio_devic /* Carrier is off until netdevice is opened */ netif_carrier_off(netdev); + /* serialize netdev register + virtio_device_ready() with ndo_open() */ + rtnl_lock(); + /* register Netdev */ - err = register_netdev(netdev); + err = register_netdevice(netdev); if (err) { + rtnl_unlock(); dev_err(&vdev->dev, "Unable to register netdev (%d)\n", err); goto err; } + virtio_device_ready(vdev); + + rtnl_unlock(); + debugfs_init(cfv); return 0;