tcp: ensure proper barriers in lockless contexts

Some functions access TCP sockets without holding a lock and
might output non consistent data, depending on compiler and or
architecture.

tcp_diag_get_info(), tcp_get_info(), tcp_poll(), get_tcp4_sock() ...

Introduce sk_state_load() and sk_state_store() to fix the issues,
and more clearly document where this lack of locking is happening.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric Dumazet 2015-11-12 08:43:18 -08:00 committed by David S. Miller
parent 5883d9c6d7
commit 00fd38d938
6 changed files with 62 additions and 23 deletions

View file

@ -21,7 +21,7 @@ static void tcp_diag_get_info(struct sock *sk, struct inet_diag_msg *r,
{
struct tcp_info *info = _info;
if (sk->sk_state == TCP_LISTEN) {
if (sk_state_load(sk) == TCP_LISTEN) {
r->idiag_rqueue = sk->sk_ack_backlog;
r->idiag_wqueue = sk->sk_max_ack_backlog;
} else if (sk->sk_type == SOCK_STREAM) {