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 13C21C433EF for ; Mon, 27 Jun 2022 11:39:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236751AbiF0LjY (ORCPT ); Mon, 27 Jun 2022 07:39:24 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34954 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236464AbiF0Lhd (ORCPT ); Mon, 27 Jun 2022 07:37:33 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CABE7639B; Mon, 27 Jun 2022 04:33:02 -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 dfw.source.kernel.org (Postfix) with ESMTPS id 49FFC60920; Mon, 27 Jun 2022 11:33:02 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 586ACC3411D; Mon, 27 Jun 2022 11:33:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1656329581; bh=VjrW0YBVZnN90T39YspyWl6ZPPln3YcYOmG1ArTMSVE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=H1GyUUaZaySG04ti4h4yvJPgud8SrkenQDAuLv9pHoa7jx/RILx8v1VEEQDBMFU0X XQAhEgcdQqYbyhFozqhgkVNjykNaw8zXQQ/i2cb3o9kWddkQ1DHjqS3NNrd7vcaBWU qRgKrle2ABYDGKHXvMbOPySLGkHJxl5KBMMJIrZ4= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Pei Zhang , "Luis Claudio R. Goncalves" , Sebastian Andrzej Siewior , "David S. Miller" , Sasha Levin Subject: [PATCH 5.15 047/135] net: Write lock dev_base_lock without disabling bottom halves. Date: Mon, 27 Jun 2022 13:20:54 +0200 Message-Id: <20220627111939.525398874@linuxfoundation.org> X-Mailer: git-send-email 2.36.1 In-Reply-To: <20220627111938.151743692@linuxfoundation.org> References: <20220627111938.151743692@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: linux-kernel@vger.kernel.org From: Sebastian Andrzej Siewior [ Upstream commit fd888e85fe6b661e78044dddfec0be5271afa626 ] The writer acquires dev_base_lock with disabled bottom halves. The reader can acquire dev_base_lock without disabling bottom halves because there is no writer in softirq context. On PREEMPT_RT the softirqs are preemptible and local_bh_disable() acts as a lock to ensure that resources, that are protected by disabling bottom halves, remain protected. This leads to a circular locking dependency if the lock acquired with disabled bottom halves (as in write_lock_bh()) and somewhere else with enabled bottom halves (as by read_lock() in netstat_show()) followed by disabling bottom halves (cxgb_get_stats() -> t4_wr_mbox_meat_timeout() -> spin_lock_bh()). This is the reverse locking order. All read_lock() invocation are from sysfs callback which are not invoked from softirq context. Therefore there is no need to disable bottom halves while acquiring a write lock. Acquire the write lock of dev_base_lock without disabling bottom halves. Reported-by: Pei Zhang Reported-by: Luis Claudio R. Goncalves Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- net/core/dev.c | 16 ++++++++-------- net/core/link_watch.c | 4 ++-- net/core/rtnetlink.c | 8 ++++---- net/hsr/hsr_device.c | 6 +++--- 4 files changed, 17 insertions(+), 17 deletions(-) diff --git a/net/core/dev.c b/net/core/dev.c index b9731b267d07..860fc6a98373 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -365,12 +365,12 @@ static void list_netdevice(struct net_device *dev) ASSERT_RTNL(); - write_lock_bh(&dev_base_lock); + write_lock(&dev_base_lock); list_add_tail_rcu(&dev->dev_list, &net->dev_base_head); netdev_name_node_add(net, dev->name_node); hlist_add_head_rcu(&dev->index_hlist, dev_index_hash(net, dev->ifindex)); - write_unlock_bh(&dev_base_lock); + write_unlock(&dev_base_lock); dev_base_seq_inc(net); } @@ -383,11 +383,11 @@ static void unlist_netdevice(struct net_device *dev) ASSERT_RTNL(); /* Unlink dev from the device chain */ - write_lock_bh(&dev_base_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_bh(&dev_base_lock); + write_unlock(&dev_base_lock); dev_base_seq_inc(dev_net(dev)); } @@ -1266,15 +1266,15 @@ int dev_change_name(struct net_device *dev, const char *newname) netdev_adjacent_rename_links(dev, oldname); - write_lock_bh(&dev_base_lock); + write_lock(&dev_base_lock); netdev_name_node_del(dev->name_node); - write_unlock_bh(&dev_base_lock); + write_unlock(&dev_base_lock); synchronize_rcu(); - write_lock_bh(&dev_base_lock); + write_lock(&dev_base_lock); netdev_name_node_add(net, dev->name_node); - write_unlock_bh(&dev_base_lock); + write_unlock(&dev_base_lock); ret = call_netdevice_notifiers(NETDEV_CHANGENAME, dev); ret = notifier_to_errno(ret); diff --git a/net/core/link_watch.c b/net/core/link_watch.c index 1a455847da54..9599afd0862d 100644 --- a/net/core/link_watch.c +++ b/net/core/link_watch.c @@ -55,7 +55,7 @@ static void rfc2863_policy(struct net_device *dev) if (operstate == dev->operstate) return; - write_lock_bh(&dev_base_lock); + write_lock(&dev_base_lock); switch(dev->link_mode) { case IF_LINK_MODE_TESTING: @@ -74,7 +74,7 @@ static void rfc2863_policy(struct net_device *dev) dev->operstate = operstate; - write_unlock_bh(&dev_base_lock); + write_unlock(&dev_base_lock); } diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c index 9c0e8ccf9bc5..8c85e93daa73 100644 --- a/net/core/rtnetlink.c +++ b/net/core/rtnetlink.c @@ -842,9 +842,9 @@ static void set_operstate(struct net_device *dev, unsigned char transition) } if (dev->operstate != operstate) { - write_lock_bh(&dev_base_lock); + write_lock(&dev_base_lock); dev->operstate = operstate; - write_unlock_bh(&dev_base_lock); + write_unlock(&dev_base_lock); netdev_state_change(dev); } } @@ -2781,11 +2781,11 @@ static int do_setlink(const struct sk_buff *skb, if (tb[IFLA_LINKMODE]) { unsigned char value = nla_get_u8(tb[IFLA_LINKMODE]); - write_lock_bh(&dev_base_lock); + write_lock(&dev_base_lock); if (dev->link_mode ^ value) status |= DO_SETLINK_NOTIFY; dev->link_mode = value; - write_unlock_bh(&dev_base_lock); + write_unlock(&dev_base_lock); } if (tb[IFLA_VFINFO_LIST]) { diff --git a/net/hsr/hsr_device.c b/net/hsr/hsr_device.c index 26c32407f029..ea7b96e296ef 100644 --- a/net/hsr/hsr_device.c +++ b/net/hsr/hsr_device.c @@ -30,13 +30,13 @@ static bool is_slave_up(struct net_device *dev) static void __hsr_set_operstate(struct net_device *dev, int transition) { - write_lock_bh(&dev_base_lock); + write_lock(&dev_base_lock); if (dev->operstate != transition) { dev->operstate = transition; - write_unlock_bh(&dev_base_lock); + write_unlock(&dev_base_lock); netdev_state_change(dev); } else { - write_unlock_bh(&dev_base_lock); + write_unlock(&dev_base_lock); } } -- 2.35.1