This is a note to let you know that I've just added the patch titled ipv4: use RCU protection in rt_is_expired() to the 6.13-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: ipv4-use-rcu-protection-in-rt_is_expired.patch and it can be found in the queue-6.13 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit a56954856102acb77e60ee54a6b7e3ed50595caf Author: Eric Dumazet <edumazet@xxxxxxxxxx> Date: Wed Feb 5 15:51:13 2025 +0000 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@xxxxxxxxxx> Reviewed-by: Kuniyuki Iwashima <kuniyu@xxxxxxxxxx> Link: https://patch.msgid.link/20250205155120.1676781-6-edumazet@xxxxxxxxxx Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/net/ipv4/route.c b/net/ipv4/route.c index 829c8d41aaae2..152697459e918 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)