netdev-genl: Hold rcu_read_lock in napi_set

Hold rcu_read_lock during netdev_nl_napi_set_doit, which calls
napi_by_id and requires rcu_read_lock to be held.

Closes: https://lore.kernel.org/netdev/719083c2-e277-447b-b6ea-ca3acb293a03@redhat.com/
Fixes: 1287c1ae0fc2 ("netdev-genl: Support setting per-NAPI config values")
Signed-off-by: Joe Damato <jdamato@fastly.com>
Link: https://patch.msgid.link/20241114175600.18882-1-jdamato@fastly.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/net/core/netdev-genl.c b/net/core/netdev-genl.c
index 765ce7c9d73b73fdafa86dc9bdc8ad533a5aaaca..fa119ff6869864fb5c08ddb8e51f63ab0a5830f6 100644 (file)
--- a/net/core/netdev-genl.c
+++ b/net/core/netdev-genl.c
@@ -346,6 +346,7 @@ int netdev_nl_napi_set_doit(struct sk_buff *skb, struct genl_info *info)
        napi_id = nla_get_u32(info->attrs[NETDEV_A_NAPI_ID]);
 
        rtnl_lock();
+       rcu_read_lock();
 
        napi = napi_by_id(napi_id);
        if (napi) {
@@ -355,6 +356,7 @@ int netdev_nl_napi_set_doit(struct sk_buff *skb, struct genl_info *info)
                err = -ENOENT;
        }
 
+       rcu_read_unlock();
        rtnl_unlock();
 
        return err;