From ad13b5b0d1f9eb8e048394919e6393e520b14552 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Fri, 3 May 2024 19:20:54 +0000 Subject: [PATCH] rtnetlink: do not depend on RTNL for IFLA_TXQLEN output rtnl_fill_ifinfo() can read dev->tx_queue_len locklessly, granted we add corresponding READ_ONCE()/WRITE_ONCE() annotations. Add missing READ_ONCE(dev->tx_queue_len) in teql_enqueue() Signed-off-by: Eric Dumazet Signed-off-by: Paolo Abeni --- net/core/dev.c | 4 ++-- net/core/rtnetlink.c | 2 +- net/sched/sch_api.c | 2 +- net/sched/sch_teql.c | 2 +- 4 files changed, 5 insertions(+), 5 deletions(-) diff --git a/net/core/dev.c b/net/core/dev.c index d6b24749eb2e..882ce6375b2e 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -8959,7 +8959,7 @@ int dev_change_tx_queue_len(struct net_device *dev, unsigned long new_len) return -ERANGE; if (new_len != orig_len) { - dev->tx_queue_len = new_len; + WRITE_ONCE(dev->tx_queue_len, new_len); res = call_netdevice_notifiers(NETDEV_CHANGE_TX_QUEUE_LEN, dev); res = notifier_to_errno(res); if (res) @@ -8973,7 +8973,7 @@ int dev_change_tx_queue_len(struct net_device *dev, unsigned long new_len) err_rollback: netdev_err(dev, "refused to change device tx_queue_len\n"); - dev->tx_queue_len = orig_len; + WRITE_ONCE(dev->tx_queue_len, orig_len); return res; } diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c index eb1a151c6910..7e156f535bd8 100644 --- a/net/core/rtnetlink.c +++ b/net/core/rtnetlink.c @@ -1837,7 +1837,7 @@ static int rtnl_fill_ifinfo(struct sk_buff *skb, if (nla_put_string(skb, IFLA_IFNAME, devname)) goto nla_put_failure; - if (nla_put_u32(skb, IFLA_TXQLEN, dev->tx_queue_len) || + if (nla_put_u32(skb, IFLA_TXQLEN, READ_ONCE(dev->tx_queue_len)) || nla_put_u8(skb, IFLA_OPERSTATE, netif_running(dev) ? dev->operstate : IF_OPER_DOWN) || nla_put_u8(skb, IFLA_LINKMODE, dev->link_mode) || diff --git a/net/sched/sch_api.c b/net/sched/sch_api.c index 6292d6d73b72..74afc210527d 100644 --- a/net/sched/sch_api.c +++ b/net/sched/sch_api.c @@ -1334,7 +1334,7 @@ static struct Qdisc *qdisc_create(struct net_device *dev, * before again attaching a qdisc. */ if ((dev->priv_flags & IFF_NO_QUEUE) && (dev->tx_queue_len == 0)) { - dev->tx_queue_len = DEFAULT_TX_QUEUE_LEN; + WRITE_ONCE(dev->tx_queue_len, DEFAULT_TX_QUEUE_LEN); netdev_info(dev, "Caught tx_queue_len zero misconfig\n"); } diff --git a/net/sched/sch_teql.c b/net/sched/sch_teql.c index 59304611dc00..29850d0f0733 100644 --- a/net/sched/sch_teql.c +++ b/net/sched/sch_teql.c @@ -78,7 +78,7 @@ teql_enqueue(struct sk_buff *skb, struct Qdisc *sch, struct sk_buff **to_free) struct net_device *dev = qdisc_dev(sch); struct teql_sched_data *q = qdisc_priv(sch); - if (q->q.qlen < dev->tx_queue_len) { + if (q->q.qlen < READ_ONCE(dev->tx_queue_len)) { __skb_queue_tail(&q->q, skb); return NET_XMIT_SUCCESS; }