From c503bc7df602257e9d03851654a347649a33f3c3 Mon Sep 17 00:00:00 2001 From: Jiri Pirko Date: Fri, 13 Oct 2023 14:10:24 +0200 Subject: [PATCH] devlink: call peernet2id_alloc() with net pointer under RCU read lock peernet2id_alloc() allows to be called lockless with peer net pointer obtained in RCU critical section and makes sure to return ns ID if net namespaces is not being removed concurrently. Benefit from read_pnet_rcu() helper addition, use it to obtain net pointer under RCU read lock and pass it to peernet2id_alloc() to get ns ID. Fixes: c137743bce02 ("devlink: introduce object and nested devlink relationship infra") Signed-off-by: Jiri Pirko Reviewed-by: Simon Horman Signed-off-by: David S. Miller --- net/devlink/netlink.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) diff --git a/net/devlink/netlink.c b/net/devlink/netlink.c index 499304d9de49..809bfc3ba8c4 100644 --- a/net/devlink/netlink.c +++ b/net/devlink/netlink.c @@ -86,18 +86,24 @@ int devlink_nl_put_nested_handle(struct sk_buff *msg, struct net *net, struct devlink *devlink, int attrtype) { struct nlattr *nested_attr; + struct net *devl_net; nested_attr = nla_nest_start(msg, attrtype); if (!nested_attr) return -EMSGSIZE; if (devlink_nl_put_handle(msg, devlink)) goto nla_put_failure; - if (!net_eq(net, devlink_net(devlink))) { - int id = peernet2id_alloc(net, devlink_net(devlink), - GFP_KERNEL); + rcu_read_lock(); + devl_net = read_pnet_rcu(&devlink->_net); + if (!net_eq(net, devl_net)) { + int id = peernet2id_alloc(net, devl_net, GFP_ATOMIC); + + rcu_read_unlock(); if (nla_put_s32(msg, DEVLINK_ATTR_NETNS_ID, id)) return -EMSGSIZE; + } else { + rcu_read_unlock(); } nla_nest_end(msg, nested_attr);