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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,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 1D75BC3F68F for ; Tue, 10 Dec 2019 21:17:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E7705207FF for ; Tue, 10 Dec 2019 21:17:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1576012671; bh=vWM0ZHYxx9xYaIp06F5yfYDOCVuzQvi6mVO4xd9HxW4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=AQhvBGpVUJF1P1LxbG4K06XBYPnVzZOvdCCq2ria/YPCeKKVcL493ifzwMJLgqhEX x6SSH6838CFuNCQ8O2akRhQMeirfpUXQqfdNo+KU0oxrT3SpbzxgDkR3dOQZrj2mZE cwEzwhCxHMFdun50BljoaQqgh8BOlDYpLe4wkho4= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729340AbfLJVRt (ORCPT ); Tue, 10 Dec 2019 16:17:49 -0500 Received: from mail.kernel.org ([198.145.29.99]:38026 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728807AbfLJVMt (ORCPT ); Tue, 10 Dec 2019 16:12:49 -0500 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 1F332214AF; Tue, 10 Dec 2019 21:12:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1576012368; bh=vWM0ZHYxx9xYaIp06F5yfYDOCVuzQvi6mVO4xd9HxW4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=G7f+mtoHYhcyedw5Xys+fegSrNqx+riavx+Z5M61i4ON7n5NLWXijBEVCTWYra6cg LjPdCgopYUqUJWWMFyDlgiScFL8PwZ8k5lo3+sRPopBRANxvwHDCYyRBRXjcWVI0SS tAeYoHvlOEhOYp2BlHssu5fq2Qon3ofDEmmR64d8= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Petar Penkov , syzbot , Eric Dumazet , "David S . Miller" , Sasha Levin , netdev@vger.kernel.org Subject: [PATCH AUTOSEL 5.4 295/350] tun: fix data-race in gro_normal_list() Date: Tue, 10 Dec 2019 16:06:40 -0500 Message-Id: <20191210210735.9077-256-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20191210210735.9077-1-sashal@kernel.org> References: <20191210210735.9077-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Petar Penkov [ Upstream commit c39e342a050a4425348e6fe7f75827c0a1a7ebc5 ] There is a race in the TUN driver between napi_busy_loop and napi_gro_frags. This commit resolves the race by adding the NAPI struct via netif_tx_napi_add, instead of netif_napi_add, which disables polling for the NAPI struct. KCSAN reported: BUG: KCSAN: data-race in gro_normal_list.part.0 / napi_busy_loop write to 0xffff8880b5d474b0 of 4 bytes by task 11205 on cpu 0: gro_normal_list.part.0+0x77/0xb0 net/core/dev.c:5682 gro_normal_list net/core/dev.c:5678 [inline] gro_normal_one net/core/dev.c:5692 [inline] napi_frags_finish net/core/dev.c:5705 [inline] napi_gro_frags+0x625/0x770 net/core/dev.c:5778 tun_get_user+0x2150/0x26a0 drivers/net/tun.c:1976 tun_chr_write_iter+0x79/0xd0 drivers/net/tun.c:2022 call_write_iter include/linux/fs.h:1895 [inline] do_iter_readv_writev+0x487/0x5b0 fs/read_write.c:693 do_iter_write fs/read_write.c:970 [inline] do_iter_write+0x13b/0x3c0 fs/read_write.c:951 vfs_writev+0x118/0x1c0 fs/read_write.c:1015 do_writev+0xe3/0x250 fs/read_write.c:1058 __do_sys_writev fs/read_write.c:1131 [inline] __se_sys_writev fs/read_write.c:1128 [inline] __x64_sys_writev+0x4e/0x60 fs/read_write.c:1128 do_syscall_64+0xcc/0x370 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x44/0xa9 read to 0xffff8880b5d474b0 of 4 bytes by task 11168 on cpu 1: gro_normal_list net/core/dev.c:5678 [inline] napi_busy_loop+0xda/0x4f0 net/core/dev.c:6126 sk_busy_loop include/net/busy_poll.h:108 [inline] __skb_recv_udp+0x4ad/0x560 net/ipv4/udp.c:1689 udpv6_recvmsg+0x29e/0xe90 net/ipv6/udp.c:288 inet6_recvmsg+0xbb/0x240 net/ipv6/af_inet6.c:592 sock_recvmsg_nosec net/socket.c:871 [inline] sock_recvmsg net/socket.c:889 [inline] sock_recvmsg+0x92/0xb0 net/socket.c:885 sock_read_iter+0x15f/0x1e0 net/socket.c:967 call_read_iter include/linux/fs.h:1889 [inline] new_sync_read+0x389/0x4f0 fs/read_write.c:414 __vfs_read+0xb1/0xc0 fs/read_write.c:427 vfs_read fs/read_write.c:461 [inline] vfs_read+0x143/0x2c0 fs/read_write.c:446 ksys_read+0xd5/0x1b0 fs/read_write.c:587 __do_sys_read fs/read_write.c:597 [inline] __se_sys_read fs/read_write.c:595 [inline] __x64_sys_read+0x4c/0x60 fs/read_write.c:595 do_syscall_64+0xcc/0x370 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Reported by Kernel Concurrency Sanitizer on: CPU: 1 PID: 11168 Comm: syz-executor.0 Not tainted 5.4.0-rc6+ #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Fixes: 943170998b20 ("tun: enable NAPI for TUN/TAP driver") Signed-off-by: Petar Penkov Reported-by: syzbot Reviewed-by: Eric Dumazet Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- drivers/net/tun.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/net/tun.c b/drivers/net/tun.c index a8d3141582a53..16564ebcde500 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -313,8 +313,8 @@ static void tun_napi_init(struct tun_struct *tun, struct tun_file *tfile, tfile->napi_enabled = napi_en; tfile->napi_frags_enabled = napi_en && napi_frags; if (napi_en) { - netif_napi_add(tun->dev, &tfile->napi, tun_napi_poll, - NAPI_POLL_WEIGHT); + netif_tx_napi_add(tun->dev, &tfile->napi, tun_napi_poll, + NAPI_POLL_WEIGHT); napi_enable(&tfile->napi); } } -- 2.20.1