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 B7FC4C43334 for ; Mon, 27 Jun 2022 11:50:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238062AbiF0LuF (ORCPT ); Mon, 27 Jun 2022 07:50:05 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48162 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238303AbiF0LsO (ORCPT ); Mon, 27 Jun 2022 07:48:14 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 75ECFF592; Mon, 27 Jun 2022 04:40:21 -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 2F377B8111B; Mon, 27 Jun 2022 11:40:20 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 61E1AC3411D; Mon, 27 Jun 2022 11:40:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1656330018; bh=NEK3lPgIPeYmxYAk6JzN0QOB+B+nIxeLsop8CrBVHCk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=EkWyBR2AtUsc+NuUyEhzurWzhx6B84Ghujg0QmGYVXPUovJgizMSdsM0gt98MyajT 249UGS+uRYDw1FoNJODwe8uTJaJ3h+UQtKhTF7E3EVGGZDkYXTgA6EhWptA5Yx9zf+ i4QTEsIuIjmh08c5/3b2nx7Ge/VfWfGLAjbttiDw= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Eric Dumazet , syzbot , "David S. Miller" , Sasha Levin Subject: [PATCH 5.18 057/181] net: fix data-race in dev_isalive() Date: Mon, 27 Jun 2022 13:20:30 +0200 Message-Id: <20220627111946.220363649@linuxfoundation.org> X-Mailer: git-send-email 2.36.1 In-Reply-To: <20220627111944.553492442@linuxfoundation.org> References: <20220627111944.553492442@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: stable@vger.kernel.org From: Eric Dumazet [ Upstream commit cc26c2661fefea215f41edb665193324a5f99021 ] dev_isalive() is called under RTNL or dev_base_lock protection. This means that changes to dev->reg_state should be done with both locks held. syzbot reported: BUG: KCSAN: data-race in register_netdevice / type_show write to 0xffff888144ecf518 of 1 bytes by task 20886 on cpu 0: register_netdevice+0xb9f/0xdf0 net/core/dev.c:10050 lapbeth_new_device drivers/net/wan/lapbether.c:414 [inline] lapbeth_device_event+0x4a0/0x6c0 drivers/net/wan/lapbether.c:456 notifier_call_chain kernel/notifier.c:87 [inline] raw_notifier_call_chain+0x53/0xb0 kernel/notifier.c:455 __dev_notify_flags+0x1d6/0x3a0 dev_change_flags+0xa2/0xc0 net/core/dev.c:8607 do_setlink+0x778/0x2230 net/core/rtnetlink.c:2780 __rtnl_newlink net/core/rtnetlink.c:3546 [inline] rtnl_newlink+0x114c/0x16a0 net/core/rtnetlink.c:3593 rtnetlink_rcv_msg+0x811/0x8c0 net/core/rtnetlink.c:6089 netlink_rcv_skb+0x13e/0x240 net/netlink/af_netlink.c:2501 rtnetlink_rcv+0x18/0x20 net/core/rtnetlink.c:6107 netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline] netlink_unicast+0x58a/0x660 net/netlink/af_netlink.c:1345 netlink_sendmsg+0x661/0x750 net/netlink/af_netlink.c:1921 sock_sendmsg_nosec net/socket.c:714 [inline] sock_sendmsg net/socket.c:734 [inline] __sys_sendto+0x21e/0x2c0 net/socket.c:2119 __do_sys_sendto net/socket.c:2131 [inline] __se_sys_sendto net/socket.c:2127 [inline] __x64_sys_sendto+0x74/0x90 net/socket.c:2127 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x46/0xb0 read to 0xffff888144ecf518 of 1 bytes by task 20423 on cpu 1: dev_isalive net/core/net-sysfs.c:38 [inline] netdev_show net/core/net-sysfs.c:50 [inline] type_show+0x24/0x90 net/core/net-sysfs.c:112 dev_attr_show+0x35/0x90 drivers/base/core.c:2095 sysfs_kf_seq_show+0x175/0x240 fs/sysfs/file.c:59 kernfs_seq_show+0x75/0x80 fs/kernfs/file.c:162 seq_read_iter+0x2c3/0x8e0 fs/seq_file.c:230 kernfs_fop_read_iter+0xd1/0x2f0 fs/kernfs/file.c:235 call_read_iter include/linux/fs.h:2052 [inline] new_sync_read fs/read_write.c:401 [inline] vfs_read+0x5a5/0x6a0 fs/read_write.c:482 ksys_read+0xe8/0x1a0 fs/read_write.c:620 __do_sys_read fs/read_write.c:630 [inline] __se_sys_read fs/read_write.c:628 [inline] __x64_sys_read+0x3e/0x50 fs/read_write.c:628 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x46/0xb0 value changed: 0x00 -> 0x01 Reported by Kernel Concurrency Sanitizer on: CPU: 1 PID: 20423 Comm: udevd Tainted: G W 5.19.0-rc2-syzkaller-dirty #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Eric Dumazet Reported-by: syzbot Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- net/core/dev.c | 25 +++++++++++++++---------- net/core/net-sysfs.c | 1 + 2 files changed, 16 insertions(+), 10 deletions(-) diff --git a/net/core/dev.c b/net/core/dev.c index 0784c339cd7d..842917883adb 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -396,16 +396,18 @@ static void list_netdevice(struct net_device *dev) /* Device list removal * caller must respect a RCU grace period before freeing/reusing dev */ -static void unlist_netdevice(struct net_device *dev) +static void unlist_netdevice(struct net_device *dev, bool lock) { ASSERT_RTNL(); /* Unlink dev from the device chain */ - write_lock(&dev_base_lock); + if (lock) + write_lock(&dev_base_lock); list_del_rcu(&dev->dev_list); netdev_name_node_del(dev->name_node); hlist_del_rcu(&dev->index_hlist); - write_unlock(&dev_base_lock); + if (lock) + write_unlock(&dev_base_lock); dev_base_seq_inc(dev_net(dev)); } @@ -9963,11 +9965,11 @@ int register_netdevice(struct net_device *dev) goto err_uninit; ret = netdev_register_kobject(dev); - if (ret) { - dev->reg_state = NETREG_UNREGISTERED; + write_lock(&dev_base_lock); + dev->reg_state = ret ? NETREG_UNREGISTERED : NETREG_REGISTERED; + write_unlock(&dev_base_lock); + if (ret) goto err_uninit; - } - dev->reg_state = NETREG_REGISTERED; __netdev_update_features(dev); @@ -10249,7 +10251,9 @@ void netdev_run_todo(void) continue; } + write_lock(&dev_base_lock); dev->reg_state = NETREG_UNREGISTERED; + write_unlock(&dev_base_lock); linkwatch_forget_dev(dev); } @@ -10727,9 +10731,10 @@ void unregister_netdevice_many(struct list_head *head) list_for_each_entry(dev, head, unreg_list) { /* And unlink it from device chain. */ - unlist_netdevice(dev); - + write_lock(&dev_base_lock); + unlist_netdevice(dev, false); dev->reg_state = NETREG_UNREGISTERING; + write_unlock(&dev_base_lock); } flush_all_backlogs(); @@ -10876,7 +10881,7 @@ int __dev_change_net_namespace(struct net_device *dev, struct net *net, dev_close(dev); /* And unlink it from device chain */ - unlist_netdevice(dev); + unlist_netdevice(dev, true); synchronize_net(); diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c index 9cbc1c8289bc..9ee57997354a 100644 --- a/net/core/net-sysfs.c +++ b/net/core/net-sysfs.c @@ -32,6 +32,7 @@ static const char fmt_dec[] = "%d\n"; static const char fmt_ulong[] = "%lu\n"; static const char fmt_u64[] = "%llu\n"; +/* Caller holds RTNL or dev_base_lock */ static inline int dev_isalive(const struct net_device *dev) { return dev->reg_state <= NETREG_REGISTERED; -- 2.35.1