From 698419ffb6fc83dd7b0359d9e8476e732967eed2 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Fri, 3 May 2024 19:20:52 +0000 Subject: rtnetlink: do not depend on RTNL for IFLA_QDISC output dev->qdisc can be read using RCU protection. Signed-off-by: Eric Dumazet Reviewed-by: Simon Horman Signed-off-by: Paolo Abeni --- net/core/rtnetlink.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c index 28050e53ecb0..ba5301d6df84 100644 --- a/net/core/rtnetlink.c +++ b/net/core/rtnetlink.c @@ -1832,7 +1832,6 @@ static int rtnl_fill_ifinfo(struct sk_buff *skb, if (tgt_netnsid >= 0 && nla_put_s32(skb, IFLA_TARGET_NETNSID, tgt_netnsid)) goto nla_put_failure; - qdisc = rtnl_dereference(dev->qdisc); if (nla_put_string(skb, IFLA_IFNAME, dev->name) || nla_put_u32(skb, IFLA_TXQLEN, dev->tx_queue_len) || nla_put_u8(skb, IFLA_OPERSTATE, @@ -1857,8 +1856,6 @@ static int rtnl_fill_ifinfo(struct sk_buff *skb, #endif put_master_ifindex(skb, dev) || nla_put_u8(skb, IFLA_CARRIER, netif_carrier_ok(dev)) || - (qdisc && - nla_put_string(skb, IFLA_QDISC, qdisc->ops->id)) || nla_put_ifalias(skb, dev) || nla_put_u32(skb, IFLA_CARRIER_CHANGES, atomic_read(&dev->carrier_up_count) + @@ -1924,6 +1921,9 @@ static int rtnl_fill_ifinfo(struct sk_buff *skb, goto nla_put_failure; rcu_read_lock(); + qdisc = rcu_dereference(dev->qdisc); + if (qdisc && nla_put_string(skb, IFLA_QDISC, qdisc->ops->id)) + goto nla_put_failure_rcu; if (rtnl_fill_link_af(skb, dev, ext_filter_mask)) goto nla_put_failure_rcu; if (rtnl_fill_link_ifmap(skb, dev)) -- cgit