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 X-Spam-Level: X-Spam-Status: No, score=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 60693C18E5B for ; Tue, 10 Mar 2020 13:19:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 39B8E20409 for ; Tue, 10 Mar 2020 13:19:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1583846350; bh=hP7QB49/EqfVLxCeySXGAPy+WtwNAdFQlnAJKdDcWTc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=hRGckPPtdJBRS82XV0sk/PiLEh0/VHZ57sxI4/wcpE86FKdbUAoRffstLuEv+gdc+ Qt4k9SZwnuQuDuIY5HSWh8Flgqcj4Y5bT87EdZ7wOkLZ0NfB+T6bmY4LLB0EAxu79l CbPzC9qc+FCY/24rksNi3NnsIz2n/tHZJz7gK3JA= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728433AbgCJNJm (ORCPT ); Tue, 10 Mar 2020 09:09:42 -0400 Received: from mail.kernel.org ([198.145.29.99]:56914 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731256AbgCJNJm (ORCPT ); Tue, 10 Mar 2020 09:09:42 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 1B5EF20873; Tue, 10 Mar 2020 13:09:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1583845781; bh=hP7QB49/EqfVLxCeySXGAPy+WtwNAdFQlnAJKdDcWTc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ndRsMaqII4iENyzZEGPxppW/sjOCBfjZ+GfDOUkAN+teFfsW2qjiDexlnI+rXwl4l Unxx//BXyMa7DFl3iRujDgGX4wr/r6iETPo90CyTWpHJiBHH1UwUTYwYeCNieLzI34 Bw+nVGOgTiscoGTXcnkqhdm2q/X1LoeTylunZxoo= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Hannes Frederic Sowa , Eric Dumazet , Jason Wang , "David S. Miller" , Tommi Rantala Subject: [PATCH 4.14 059/126] tuntap: correctly set SOCKWQ_ASYNC_NOSPACE Date: Tue, 10 Mar 2020 13:41:20 +0100 Message-Id: <20200310124207.925139999@linuxfoundation.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200310124203.704193207@linuxfoundation.org> References: <20200310124203.704193207@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Jason Wang commit 2f3ab6221e4c87960347d65c7cab9bd917d1f637 upstream. When link is down, writes to the device might fail with -EIO. Userspace needs an indication when the status is resolved. As a fix, tun_net_open() attempts to wake up writers - but that is only effective if SOCKWQ_ASYNC_NOSPACE has been set in the past. This is not the case of vhost_net which only poll for EPOLLOUT after it meets errors during sendmsg(). This patch fixes this by making sure SOCKWQ_ASYNC_NOSPACE is set when socket is not writable or device is down to guarantee EPOLLOUT will be raised in either tun_chr_poll() or tun_sock_write_space() after device is up. Cc: Hannes Frederic Sowa Cc: Eric Dumazet Fixes: 1bd4978a88ac2 ("tun: honor IFF_UP in tun_get_user()") Signed-off-by: Jason Wang Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman Signed-off-by: Tommi Rantala --- drivers/net/tun.c | 19 +++++++++++++++---- 1 file changed, 15 insertions(+), 4 deletions(-) --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -1134,6 +1134,13 @@ static void tun_net_init(struct net_devi dev->max_mtu = MAX_MTU - dev->hard_header_len; } +static bool tun_sock_writeable(struct tun_struct *tun, struct tun_file *tfile) +{ + struct sock *sk = tfile->socket.sk; + + return (tun->dev->flags & IFF_UP) && sock_writeable(sk); +} + /* Character device part */ /* Poll */ @@ -1156,10 +1163,14 @@ static unsigned int tun_chr_poll(struct if (!skb_array_empty(&tfile->tx_array)) mask |= POLLIN | POLLRDNORM; - if (tun->dev->flags & IFF_UP && - (sock_writeable(sk) || - (!test_and_set_bit(SOCKWQ_ASYNC_NOSPACE, &sk->sk_socket->flags) && - sock_writeable(sk)))) + /* Make sure SOCKWQ_ASYNC_NOSPACE is set if not writable to + * guarantee EPOLLOUT to be raised by either here or + * tun_sock_write_space(). Then process could get notification + * after it writes to a down device and meets -EIO. + */ + if (tun_sock_writeable(tun, tfile) || + (!test_and_set_bit(SOCKWQ_ASYNC_NOSPACE, &sk->sk_socket->flags) && + tun_sock_writeable(tun, tfile))) mask |= POLLOUT | POLLWRNORM; if (tun->dev->reg_state != NETREG_REGISTERED)