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=-19.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,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 AB613C49EB9 for ; Mon, 28 Jun 2021 14:22:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8831160233 for ; Mon, 28 Jun 2021 14:22:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232623AbhF1OYX (ORCPT ); Mon, 28 Jun 2021 10:24:23 -0400 Received: from mail.kernel.org ([198.145.29.99]:55032 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233137AbhF1OVa (ORCPT ); Mon, 28 Jun 2021 10:21:30 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 9141461C7C; Mon, 28 Jun 2021 14:19:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1624889945; bh=gdwqziYej5UQV+KrdT1l+V7grfC5iPSlLrDqLs8FbAY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=XXua5XaHRwIHdt9OjzwIH8+Blyk9D4xhRo/RBgBrw1csrswGcQ5gKfS05l8RQThtp p6oChauc1OURd+79Ip914qQSwB/OLGnfk47OQSElOM0slB/tVqrlQya7TnBqFY2s+C YEZIxeordcz8LFa7IHwl7sBEKZkivoxhqOtEnQA2tRj9XiniTpLbas6oJqFmzVTajw Pm2z14oVpUAi9/60+x5lwKdjnw/wulEj7jZ3V3Le3Ky/P6oMmavqfv9NO9NAih9Xqf M3mcb/JxY67hmRlf/LdvzNr2bUt/z0GEp5jDYpIHC5CxsPNHET6d8Zcd7Rkz4cV6FY DL3gDYg3znoEw== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Eric Dumazet , "David S . Miller" , Sasha Levin Subject: [PATCH 5.12 041/110] net/packet: annotate data race in packet_sendmsg() Date: Mon, 28 Jun 2021 10:17:19 -0400 Message-Id: <20210628141828.31757-42-sashal@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210628141828.31757-1-sashal@kernel.org> References: <20210628141828.31757-1-sashal@kernel.org> MIME-Version: 1.0 X-KernelTest-Patch: http://kernel.org/pub/linux/kernel/v5.x/stable-review/patch-5.12.14-rc1.gz X-KernelTest-Tree: git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git X-KernelTest-Branch: linux-5.12.y X-KernelTest-Patches: git://git.kernel.org/pub/scm/linux/kernel/git/stable/stable-queue.git X-KernelTest-Version: 5.12.14-rc1 X-KernelTest-Deadline: 2021-06-30T14:18+00:00 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Eric Dumazet [ Upstream commit d1b5bee4c8be01585033be9b3a8878789285285f ] There is a known race in packet_sendmsg(), addressed in commit 32d3182cd2cd ("net/packet: fix race in tpacket_snd()") Now we have data_race(), we can use it to avoid a future KCSAN warning, as syzbot loves stressing af_packet sockets :) Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- net/packet/af_packet.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c index c52557ec7fb3..84d8921391c3 100644 --- a/net/packet/af_packet.c +++ b/net/packet/af_packet.c @@ -3034,10 +3034,13 @@ static int packet_sendmsg(struct socket *sock, struct msghdr *msg, size_t len) struct sock *sk = sock->sk; struct packet_sock *po = pkt_sk(sk); - if (po->tx_ring.pg_vec) + /* Reading tx_ring.pg_vec without holding pg_vec_lock is racy. + * tpacket_snd() will redo the check safely. + */ + if (data_race(po->tx_ring.pg_vec)) return tpacket_snd(po, msg); - else - return packet_snd(sock, msg, len); + + return packet_snd(sock, msg, len); } /* -- 2.30.2