raw: Fix a data-race around sysctl_raw_l3mdev_accept.

[ Upstream commit 1dace01492 ]

While reading sysctl_raw_l3mdev_accept, it can be changed concurrently.
Thus, we need to add READ_ONCE() to its reader.

Fixes: 6897445fb1 ("net: provide a sysctl raw_l3mdev_accept for raw socket lookup with VRFs")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>

include/net/raw.h

@@ -75,7 +75,7 @@ static inline bool raw_sk_bound_dev_eq(struct net *net, int bound_dev_if,
 				       int dif, int sdif)
 {
 #if IS_ENABLED(CONFIG_NET_L3_MASTER_DEV)
-	return inet_bound_dev_eq(!!net->ipv4.sysctl_raw_l3mdev_accept,
+	return inet_bound_dev_eq(READ_ONCE(net->ipv4.sysctl_raw_l3mdev_accept),
 				 bound_dev_if, dif, sdif);
 #else
 	return inet_bound_dev_eq(true, bound_dev_if, dif, sdif);