tcp: Fix a data-race around sysctl_tcp_abort_on_overflow.

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

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv4/tcp_minisocks.c b/net/ipv4/tcp_minisocks.c
index 700ea54..cb95d88 100644 (file)
--- a/net/ipv4/tcp_minisocks.c
+++ b/net/ipv4/tcp_minisocks.c
@@ -781,7 +781,7 @@ listen_overflow:
        if (sk != req->rsk_listener)
                __NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMIGRATEREQFAILURE);
 
-       if (!sock_net(sk)->ipv4.sysctl_tcp_abort_on_overflow) {
+       if (!READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_abort_on_overflow)) {
                inet_rsk(req)->acked = 1;
                return NULL;
        }