From ddb6845c2464143ed539a2249f47466f0a53a8a3 Mon Sep 17 00:00:00 2001
From: Eric Dumazet <edumazet@google.com>
Date: Wed, 5 Feb 2025 15:51:13 +0000
Subject: [PATCH] ipv4: use RCU protection in rt_is_expired()
[ Upstream commit dd205fcc33d92d54eee4d7f21bb073af9bd5ce2b ]
rt_is_expired() must use RCU protection to make
sure the net structure it reads does not disappear.
Fixes: e84f84f27647 ("netns: place rt_genid into struct net")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Link: https://patch.msgid.link/20250205155120.1676781-6-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
net/ipv4/route.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 5f18520d054c0..ae56d94f68d9f 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -393,7 +393,13 @@ static inline int ip_rt_proc_init(void)
static inline bool rt_is_expired(const struct rtable *rth)
{
- return rth->rt_genid != rt_genid_ipv4(dev_net(rth->dst.dev));
+ bool res;
+
+ rcu_read_lock();
+ res = rth->rt_genid != rt_genid_ipv4(dev_net_rcu(rth->dst.dev));
+ rcu_read_unlock();
+
+ return res;
}
void rt_cache_flush(struct net *net)
--
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