Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754769AbcDRC7V (ORCPT ); Sun, 17 Apr 2016 22:59:21 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:36633 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754630AbcDRChr (ORCPT ); Sun, 17 Apr 2016 22:37:47 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Eric Dumazet , Andy Gospodarek , Jay Vosburgh , Veaceslav Falico , Nikolay Aleksandrov , "David S. Miller" Subject: [PATCH 4.4 064/137] bonding: fix bond_get_stats() Date: Mon, 18 Apr 2016 11:28:46 +0900 Message-Id: <20160418022511.499193779@linuxfoundation.org> X-Mailer: git-send-email 2.8.0 In-Reply-To: <20160418022507.236379264@linuxfoundation.org> References: <20160418022507.236379264@linuxfoundation.org> User-Agent: quilt/0.64 MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5177 Lines: 141 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Eric Dumazet [ Upstream commit fe30937b65354c7fec244caebbdaae68e28ca797 ] bond_get_stats() can be called from rtnetlink (with RTNL held) or from /proc/net/dev seq handler (with RCU held) The logic added in commit 5f0c5f73e5ef ("bonding: make global bonding stats more reliable") kind of assumed only one cpu could run there. If multiple threads are reading /proc/net/dev, stats can be really messed up after a while. A second problem is that some fields are 32bit, so we need to properly handle the wrap around problem. Given that RTNL is not always held, we need to use bond_for_each_slave_rcu(). Fixes: 5f0c5f73e5ef ("bonding: make global bonding stats more reliable") Signed-off-by: Eric Dumazet Cc: Andy Gospodarek Cc: Jay Vosburgh Cc: Veaceslav Falico Reviewed-by: Nikolay Aleksandrov Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- drivers/net/bonding/bond_main.c | 63 +++++++++++++++++++++------------------- include/net/bonding.h | 1 2 files changed, 35 insertions(+), 29 deletions(-) --- a/drivers/net/bonding/bond_main.c +++ b/drivers/net/bonding/bond_main.c @@ -3260,6 +3260,30 @@ static int bond_close(struct net_device return 0; } +/* fold stats, assuming all rtnl_link_stats64 fields are u64, but + * that some drivers can provide 32bit values only. + */ +static void bond_fold_stats(struct rtnl_link_stats64 *_res, + const struct rtnl_link_stats64 *_new, + const struct rtnl_link_stats64 *_old) +{ + const u64 *new = (const u64 *)_new; + const u64 *old = (const u64 *)_old; + u64 *res = (u64 *)_res; + int i; + + for (i = 0; i < sizeof(*_res) / sizeof(u64); i++) { + u64 nv = new[i]; + u64 ov = old[i]; + + /* detects if this particular field is 32bit only */ + if (((nv | ov) >> 32) == 0) + res[i] += (u32)nv - (u32)ov; + else + res[i] += nv - ov; + } +} + static struct rtnl_link_stats64 *bond_get_stats(struct net_device *bond_dev, struct rtnl_link_stats64 *stats) { @@ -3268,43 +3292,23 @@ static struct rtnl_link_stats64 *bond_ge struct list_head *iter; struct slave *slave; + spin_lock(&bond->stats_lock); memcpy(stats, &bond->bond_stats, sizeof(*stats)); - bond_for_each_slave(bond, slave, iter) { - const struct rtnl_link_stats64 *sstats = + rcu_read_lock(); + bond_for_each_slave_rcu(bond, slave, iter) { + const struct rtnl_link_stats64 *new = dev_get_stats(slave->dev, &temp); - struct rtnl_link_stats64 *pstats = &slave->slave_stats; - stats->rx_packets += sstats->rx_packets - pstats->rx_packets; - stats->rx_bytes += sstats->rx_bytes - pstats->rx_bytes; - stats->rx_errors += sstats->rx_errors - pstats->rx_errors; - stats->rx_dropped += sstats->rx_dropped - pstats->rx_dropped; - - stats->tx_packets += sstats->tx_packets - pstats->tx_packets;; - stats->tx_bytes += sstats->tx_bytes - pstats->tx_bytes; - stats->tx_errors += sstats->tx_errors - pstats->tx_errors; - stats->tx_dropped += sstats->tx_dropped - pstats->tx_dropped; - - stats->multicast += sstats->multicast - pstats->multicast; - stats->collisions += sstats->collisions - pstats->collisions; - - stats->rx_length_errors += sstats->rx_length_errors - pstats->rx_length_errors; - stats->rx_over_errors += sstats->rx_over_errors - pstats->rx_over_errors; - stats->rx_crc_errors += sstats->rx_crc_errors - pstats->rx_crc_errors; - stats->rx_frame_errors += sstats->rx_frame_errors - pstats->rx_frame_errors; - stats->rx_fifo_errors += sstats->rx_fifo_errors - pstats->rx_fifo_errors; - stats->rx_missed_errors += sstats->rx_missed_errors - pstats->rx_missed_errors; - - stats->tx_aborted_errors += sstats->tx_aborted_errors - pstats->tx_aborted_errors; - stats->tx_carrier_errors += sstats->tx_carrier_errors - pstats->tx_carrier_errors; - stats->tx_fifo_errors += sstats->tx_fifo_errors - pstats->tx_fifo_errors; - stats->tx_heartbeat_errors += sstats->tx_heartbeat_errors - pstats->tx_heartbeat_errors; - stats->tx_window_errors += sstats->tx_window_errors - pstats->tx_window_errors; + bond_fold_stats(stats, new, &slave->slave_stats); /* save off the slave stats for the next run */ - memcpy(pstats, sstats, sizeof(*sstats)); + memcpy(&slave->slave_stats, new, sizeof(*new)); } + rcu_read_unlock(); + memcpy(&bond->bond_stats, stats, sizeof(*stats)); + spin_unlock(&bond->stats_lock); return stats; } @@ -4118,6 +4122,7 @@ void bond_setup(struct net_device *bond_ struct bonding *bond = netdev_priv(bond_dev); spin_lock_init(&bond->mode_lock); + spin_lock_init(&bond->stats_lock); bond->params = bonding_defaults; /* Initialize pointers */ --- a/include/net/bonding.h +++ b/include/net/bonding.h @@ -214,6 +214,7 @@ struct bonding { * ALB mode (6) - to sync the use and modifications of its hash table */ spinlock_t mode_lock; + spinlock_t stats_lock; u8 send_peer_notif; u8 igmp_retrans; #ifdef CONFIG_PROC_FS