[PATCH v5 net-next 4/5] rtnetlink: do not assume RTNL is held in link_master_filtered()
From: Eric Dumazet <edumazet@google.com>
Date: 2026-05-25 08:35:51
Subsystem:
networking [general], the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
RTNL might be no longer held by the caller in the following patch. Signed-off-by: Eric Dumazet <edumazet@google.com> --- net/core/rtnetlink.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-)
diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index 6041e008b22dbfd164ede6d50a77d2db5d7e2e23..0a59036d5f933c5b2f123a47e059036d2a555911 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c@@ -2371,22 +2371,24 @@ static struct rtnl_link_ops *linkinfo_to_kind_ops(const struct nlattr *nla, static bool link_master_filtered(struct net_device *dev, int master_idx) { struct net_device *master; + bool res = false; if (!master_idx) return false; - master = netdev_master_upper_dev_get(dev); + rcu_read_lock(); + master = netdev_master_upper_dev_get_rcu(dev); /* 0 is already used to denote IFLA_MASTER wasn't passed, therefore need * another invalid value for ifindex to denote "no master". */ if (master_idx == -1) - return !!master; - - if (!master || master->ifindex != master_idx) - return true; + res = !!master; + else if (!master || master->ifindex != master_idx) + res = true; + rcu_read_unlock(); - return false; + return res; } static bool link_kind_filtered(const struct net_device *dev,
--
2.54.0.746.g67dd491aae-goog