From dd205fcc33d92d54eee4d7f21bb073af9bd5ce2b Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Wed, 5 Feb 2025 15:51:13 +0000 Subject: [PATCH] ipv4: use RCU protection in rt_is_expired() 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 Reviewed-by: Kuniyuki Iwashima Link: https://patch.msgid.link/20250205155120.1676781-6-edumazet@google.com Signed-off-by: Jakub Kicinski --- 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 74c074f45758..e959327c0ba8 100644 --- a/net/ipv4/route.c +++ b/net/ipv4/route.c @@ -390,7 +390,13 @@ 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)