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=-16.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham 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 42220C71155 for ; Thu, 3 Dec 2020 08:02:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D3FEC20C56 for ; Thu, 3 Dec 2020 08:02:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729907AbgLCIC3 (ORCPT ); Thu, 3 Dec 2020 03:02:29 -0500 Received: from szxga07-in.huawei.com ([45.249.212.35]:8926 "EHLO szxga07-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726539AbgLCIC3 (ORCPT ); Thu, 3 Dec 2020 03:02:29 -0500 Received: from DGGEMS414-HUB.china.huawei.com (unknown [172.30.72.59]) by szxga07-in.huawei.com (SkyGuard) with ESMTP id 4CmpFC5J89z782w; Thu, 3 Dec 2020 16:01:19 +0800 (CST) Received: from localhost (10.174.187.156) by DGGEMS414-HUB.china.huawei.com (10.3.19.214) with Microsoft SMTP Server id 14.3.487.0; Thu, 3 Dec 2020 16:01:39 +0800 From: wangyunjian To: , CC: , , , , Yunjian Wang Subject: [PATCH net-next] tun: fix ubuf refcount incorrectly on error path Date: Thu, 3 Dec 2020 16:00:59 +0800 Message-ID: <1606982459-41752-1-git-send-email-wangyunjian@huawei.com> X-Mailer: git-send-email 1.9.5.msysgit.1 MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [10.174.187.156] X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Yunjian Wang After setting callback for ubuf_info of skb, the callback (vhost_net_zerocopy_callback) will be called to decrease the refcount when freeing skb. But when an exception occurs afterwards, the error handling in vhost handle_tx() will try to decrease the same refcount again. This is wrong and fix this by clearing ubuf_info when meeting errors. Fixes: 4477138fa0ae ("tun: properly test for IFF_UP") Fixes: 90e33d459407 ("tun: enable napi_gro_frags() for TUN/TAP driver") Signed-off-by: Yunjian Wang --- drivers/net/tun.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/drivers/net/tun.c b/drivers/net/tun.c index 2dc1988a8973..3614bb1b6d35 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -1861,6 +1861,12 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile, if (unlikely(!(tun->dev->flags & IFF_UP))) { err = -EIO; rcu_read_unlock(); + if (zerocopy) { + skb_shinfo(skb)->destructor_arg = NULL; + skb_shinfo(skb)->tx_flags &= ~SKBTX_DEV_ZEROCOPY; + skb_shinfo(skb)->tx_flags &= ~SKBTX_SHARED_FRAG; + } + goto drop; } @@ -1874,6 +1880,11 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile, if (unlikely(headlen > skb_headlen(skb))) { atomic_long_inc(&tun->dev->rx_dropped); + if (zerocopy) { + skb_shinfo(skb)->destructor_arg = NULL; + skb_shinfo(skb)->tx_flags &= ~SKBTX_DEV_ZEROCOPY; + skb_shinfo(skb)->tx_flags &= ~SKBTX_SHARED_FRAG; + } napi_free_frags(&tfile->napi); rcu_read_unlock(); mutex_unlock(&tfile->napi_mutex); -- 2.18.1