[PATCH net v3] netdev-genl: Hold rcu_read_lock in napi_get

[Joe Damato <jdamato@fastly.com>]

Hold rcu_read_lock in netdev_nl_napi_get_doit, which calls napi_by_id
and is required to be called under rcu_read_lock.

Cc: stable@vger.kernel.org
Fixes: 27f91aaf49b3 ("netdev-genl: Add netlink framework functions for napi")
Signed-off-by: Joe Damato <jdamato@fastly.com>
---
 v3:
   - Separate the patches that were a series in v2 (and earlier) as
     they target different trees.

 v2:
   - Simplified by removing the helper and calling rcu_read_lock /
     unlock directly instead.

 net/core/netdev-genl.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/net/core/netdev-genl.c b/net/core/netdev-genl.c
index 1cb954f2d39e..d2baa1af9df0 100644
--- a/net/core/netdev-genl.c
+++ b/net/core/netdev-genl.c
@@ -215,6 +215,7 @@ int netdev_nl_napi_get_doit(struct sk_buff *skb, struct genl_info *info)
 		return -ENOMEM;
 
 	rtnl_lock();
+	rcu_read_lock();
 
 	napi = napi_by_id(napi_id);
 	if (napi) {
@@ -224,6 +225,7 @@ int netdev_nl_napi_get_doit(struct sk_buff *skb, struct genl_info *info)
 		err = -ENOENT;
 	}
 
+	rcu_read_unlock();
 	rtnl_unlock();
 
 	if (err)

base-commit: 5b366eae71937ae7412365340b431064625f9617
-- 
2.25.1