From 1e37200e2c1760101aa32326a9ece5cb891a6656 Mon Sep 17 00:00:00 2001
From: Eric Dumazet <edumazet@google.com>
Date: Wed, 5 Feb 2025 15:51:09 +0000
Subject: [PATCH] net: add dev_net_rcu() helper
[ Upstream commit 482ad2a4ace2740ca0ff1cbc8f3c7f862f3ab507 ]
dev->nd_net can change, readers should either
use rcu_read_lock() or RTNL.
We currently use a generic helper, dev_net() with
no debugging support. We probably have many hidden bugs.
Add dev_net_rcu() helper for callers using rcu_read_lock()
protection.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Link: https://patch.msgid.link/20250205155120.1676781-2-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Stable-dep-of: 71b8471c93fa ("ipv4: use RCU protection in ipv4_default_advmss()")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
include/linux/netdevice.h | 6 ++++++
include/net/net_namespace.h | 2 +-
2 files changed, 7 insertions(+), 1 deletion(-)
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index c75aed1fff7d1..d0b4920dee730 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -2538,6 +2538,12 @@ struct net *dev_net(const struct net_device *dev)
return read_pnet(&dev->nd_net);
}
+static inline
+struct net *dev_net_rcu(const struct net_device *dev)
+{
+ return read_pnet_rcu(&dev->nd_net);
+}
+
static inline
void dev_net_set(struct net_device *dev, struct net *net)
{
diff --git a/include/net/net_namespace.h b/include/net/net_namespace.h
index 3ffcc1b02a590..ee50d54936629 100644
--- a/include/net/net_namespace.h
+++ b/include/net/net_namespace.h
@@ -373,7 +373,7 @@ static inline struct net *read_pnet(const possible_net_t *pnet)
#endif
}
-static inline struct net *read_pnet_rcu(possible_net_t *pnet)
+static inline struct net *read_pnet_rcu(const possible_net_t *pnet)
{
#ifdef CONFIG_NET_NS
return rcu_dereference(pnet->net);
--
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