net: annotate data-races around sk->sk_dst_pending_confirm

[ Upstream commit eb44ad4e635132754bfbcb18103f1dcb7058aedd ]

This field can be read or written without socket lock being held.

Add annotations to avoid load-store tearing.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/include/net/sock.h b/include/net/sock.h
index 7b42ddca4decbe214350f0c2d2c9a2ba57f36d90..f974b548e1199f0fcd6fc73ae07aac4b411d3d96 100644 (file)
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -1804,7 +1804,7 @@ static inline void dst_negative_advice(struct sock *sk)
                if (ndst != dst) {
                        rcu_assign_pointer(sk->sk_dst_cache, ndst);
                        sk_tx_queue_clear(sk);
-                       sk->sk_dst_pending_confirm = 0;
+                       WRITE_ONCE(sk->sk_dst_pending_confirm, 0);
                }
        }
 }
@@ -1815,7 +1815,7 @@ __sk_dst_set(struct sock *sk, struct dst_entry *dst)
        struct dst_entry *old_dst;
 
        sk_tx_queue_clear(sk);
-       sk->sk_dst_pending_confirm = 0;
+       WRITE_ONCE(sk->sk_dst_pending_confirm, 0);
        old_dst = rcu_dereference_protected(sk->sk_dst_cache,
                                            lockdep_sock_is_held(sk));
        rcu_assign_pointer(sk->sk_dst_cache, dst);
@@ -1828,7 +1828,7 @@ sk_dst_set(struct sock *sk, struct dst_entry *dst)
        struct dst_entry *old_dst;
 
        sk_tx_queue_clear(sk);
-       sk->sk_dst_pending_confirm = 0;
+       WRITE_ONCE(sk->sk_dst_pending_confirm, 0);
        old_dst = xchg((__force struct dst_entry **)&sk->sk_dst_cache, dst);
        dst_release(old_dst);
 }

diff --git a/net/core/sock.c b/net/core/sock.c
index 5b9f51a27dc0db1fd12abaca998289f821efaeb6..e8b5742d9149230797b709cec83a200c317400c8 100644 (file)
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -534,7 +534,7 @@ struct dst_entry *__sk_dst_check(struct sock *sk, u32 cookie)
 
        if (dst && dst->obsolete && dst->ops->check(dst, cookie) == NULL) {
                sk_tx_queue_clear(sk);
-               sk->sk_dst_pending_confirm = 0;
+               WRITE_ONCE(sk->sk_dst_pending_confirm, 0);
                RCU_INIT_POINTER(sk->sk_dst_cache, NULL);
                dst_release(dst);
                return NULL;

diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index 8b2d49120ce23800a93fdc21e02a41d6b73fc191..67636017f275a382b307bef641d348ce80c07708 100644 (file)
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -1059,7 +1059,7 @@ static int __tcp_transmit_skb(struct sock *sk, struct sk_buff *skb,
        skb_set_hash_from_sk(skb, sk);
        refcount_add(skb->truesize, &sk->sk_wmem_alloc);
 
-       skb_set_dst_pending_confirm(skb, sk->sk_dst_pending_confirm);
+       skb_set_dst_pending_confirm(skb, READ_ONCE(sk->sk_dst_pending_confirm));
 
        /* Build TCP header and checksum it. */
        th = (struct tcphdr *)skb->data;