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Diffstat (limited to 'net')
-rw-r--r--net/core/sock.c20
1 files changed, 18 insertions, 2 deletions
diff --git a/net/core/sock.c b/net/core/sock.c
index ba5d2116aea..d9eec153d53 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -919,13 +919,19 @@ static inline void sock_lock_init(struct sock *sk)
af_family_keys + sk->sk_family);
}
+/*
+ * Copy all fields from osk to nsk but nsk->sk_refcnt must not change yet,
+ * even temporarly, because of RCU lookups. sk_node should also be left as is.
+ */
static void sock_copy(struct sock *nsk, const struct sock *osk)
{
#ifdef CONFIG_SECURITY_NETWORK
void *sptr = nsk->sk_security;
#endif
-
- memcpy(nsk, osk, osk->sk_prot->obj_size);
+ BUILD_BUG_ON(offsetof(struct sock, sk_copy_start) !=
+ sizeof(osk->sk_node) + sizeof(osk->sk_refcnt));
+ memcpy(&nsk->sk_copy_start, &osk->sk_copy_start,
+ osk->sk_prot->obj_size - offsetof(struct sock, sk_copy_start));
#ifdef CONFIG_SECURITY_NETWORK
nsk->sk_security = sptr;
security_sk_clone(osk, nsk);
@@ -1140,6 +1146,11 @@ struct sock *sk_clone(const struct sock *sk, const gfp_t priority)
newsk->sk_err = 0;
newsk->sk_priority = 0;
+ /*
+ * Before updating sk_refcnt, we must commit prior changes to memory
+ * (Documentation/RCU/rculist_nulls.txt for details)
+ */
+ smp_wmb();
atomic_set(&newsk->sk_refcnt, 2);
/*
@@ -1855,6 +1866,11 @@ void sock_init_data(struct socket *sock, struct sock *sk)
sk->sk_stamp = ktime_set(-1L, 0);
+ /*
+ * Before updating sk_refcnt, we must commit prior changes to memory
+ * (Documentation/RCU/rculist_nulls.txt for details)
+ */
+ smp_wmb();
atomic_set(&sk->sk_refcnt, 1);
atomic_set(&sk->sk_wmem_alloc, 1);
atomic_set(&sk->sk_drops, 0);