tcp: annotate data-races around tw->tw_ts_recent and tw->tw_ts_recent_stamp

These fields can be read and written locklessly, add annotations
around these minor races.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 04044605cadf1ffe86b4fa9bc75c1ff812f7f053..3ef4b274c24b8dca950a50eaf2efb800898dad3e 100644 (file)
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -114,6 +114,7 @@ int tcp_twsk_unique(struct sock *sk, struct sock *sktw, void *twp)
        const struct inet_timewait_sock *tw = inet_twsk(sktw);
        const struct tcp_timewait_sock *tcptw = tcp_twsk(sktw);
        struct tcp_sock *tp = tcp_sk(sk);
+       int ts_recent_stamp;
 
        if (reuse == 2) {
                /* Still does not detect *everything* that goes through
@@ -152,9 +153,10 @@ int tcp_twsk_unique(struct sock *sk, struct sock *sktw, void *twp)
           If TW bucket has been already destroyed we fall back to VJ's scheme
           and use initial timestamp retrieved from peer table.
         */
-       if (tcptw->tw_ts_recent_stamp &&
+       ts_recent_stamp = READ_ONCE(tcptw->tw_ts_recent_stamp);
+       if (ts_recent_stamp &&
            (!twp || (reuse && time_after32(ktime_get_seconds(),
-                                           tcptw->tw_ts_recent_stamp)))) {
+                                           ts_recent_stamp)))) {
                /* inet_twsk_hashdance() sets sk_refcnt after putting twsk
                 * and releasing the bucket lock.
                 */
@@ -178,8 +180,8 @@ int tcp_twsk_unique(struct sock *sk, struct sock *sktw, void *twp)
                        if (!seq)
                                seq = 1;
                        WRITE_ONCE(tp->write_seq, seq);
-                       tp->rx_opt.ts_recent       = tcptw->tw_ts_recent;
-                       tp->rx_opt.ts_recent_stamp = tcptw->tw_ts_recent_stamp;
+                       tp->rx_opt.ts_recent       = READ_ONCE(tcptw->tw_ts_recent);
+                       tp->rx_opt.ts_recent_stamp = ts_recent_stamp;
                }
 
                return 1;
@@ -1064,7 +1066,7 @@ static void tcp_v4_timewait_ack(struct sock *sk, struct sk_buff *skb)
                        tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
                        tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale,
                        tcp_tw_tsval(tcptw),
-                       tcptw->tw_ts_recent,
+                       READ_ONCE(tcptw->tw_ts_recent),
                        tw->tw_bound_dev_if, &key,
                        tw->tw_transparent ? IP_REPLY_ARG_NOSRCCHECK : 0,
                        tw->tw_tos,

diff --git a/net/ipv4/tcp_minisocks.c b/net/ipv4/tcp_minisocks.c
index 538c06f95918dedf29e0f4790795fcc417f2516f..4c894e540730ab6cbec6e781b72a4cb3cf4c55b4 100644 (file)
--- a/net/ipv4/tcp_minisocks.c
+++ b/net/ipv4/tcp_minisocks.c
@@ -101,16 +101,18 @@ tcp_timewait_state_process(struct inet_timewait_sock *tw, struct sk_buff *skb,
        struct tcp_options_received tmp_opt;
        struct tcp_timewait_sock *tcptw = tcp_twsk((struct sock *)tw);
        bool paws_reject = false;
+       int ts_recent_stamp;
 
        tmp_opt.saw_tstamp = 0;
-       if (th->doff > (sizeof(*th) >> 2) && tcptw->tw_ts_recent_stamp) {
+       ts_recent_stamp = READ_ONCE(tcptw->tw_ts_recent_stamp);
+       if (th->doff > (sizeof(*th) >> 2) && ts_recent_stamp) {
                tcp_parse_options(twsk_net(tw), skb, &tmp_opt, 0, NULL);
 
                if (tmp_opt.saw_tstamp) {
                        if (tmp_opt.rcv_tsecr)
                                tmp_opt.rcv_tsecr -= tcptw->tw_ts_offset;
-                       tmp_opt.ts_recent       = tcptw->tw_ts_recent;
-                       tmp_opt.ts_recent_stamp = tcptw->tw_ts_recent_stamp;
+                       tmp_opt.ts_recent       = READ_ONCE(tcptw->tw_ts_recent);
+                       tmp_opt.ts_recent_stamp = ts_recent_stamp;
                        paws_reject = tcp_paws_reject(&tmp_opt, th->rst);
                }
        }
@@ -152,8 +154,10 @@ tcp_timewait_state_process(struct inet_timewait_sock *tw, struct sk_buff *skb,
                twsk_rcv_nxt_update(tcptw, TCP_SKB_CB(skb)->end_seq);
 
                if (tmp_opt.saw_tstamp) {
-                       tcptw->tw_ts_recent_stamp = ktime_get_seconds();
-                       tcptw->tw_ts_recent       = tmp_opt.rcv_tsval;
+                       WRITE_ONCE(tcptw->tw_ts_recent_stamp,
+                                 ktime_get_seconds());
+                       WRITE_ONCE(tcptw->tw_ts_recent,
+                                  tmp_opt.rcv_tsval);
                }
 
                inet_twsk_reschedule(tw, TCP_TIMEWAIT_LEN);
@@ -197,8 +201,10 @@ kill:
                }
 
                if (tmp_opt.saw_tstamp) {
-                       tcptw->tw_ts_recent       = tmp_opt.rcv_tsval;
-                       tcptw->tw_ts_recent_stamp = ktime_get_seconds();
+                       WRITE_ONCE(tcptw->tw_ts_recent,
+                                  tmp_opt.rcv_tsval);
+                       WRITE_ONCE(tcptw->tw_ts_recent_stamp,
+                                  ktime_get_seconds());
                }
 
                inet_twsk_put(tw);
@@ -225,7 +231,7 @@ kill:
        if (th->syn && !th->rst && !th->ack && !paws_reject &&
            (after(TCP_SKB_CB(skb)->seq, tcptw->tw_rcv_nxt) ||
             (tmp_opt.saw_tstamp &&
-             (s32)(tcptw->tw_ts_recent - tmp_opt.rcv_tsval) < 0))) {
+             (s32)(READ_ONCE(tcptw->tw_ts_recent) - tmp_opt.rcv_tsval) < 0))) {
                u32 isn = tcptw->tw_snd_nxt + 65535 + 2;
                if (isn == 0)
                        isn++;

diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index 5fe4365de89dd145bba521ec88a74bc2154dc760..f4777c03cdd7a1f43c50901eca8e185d1e3a394c 100644 (file)
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -1196,9 +1196,9 @@ static void tcp_v6_timewait_ack(struct sock *sk, struct sk_buff *skb)
        tcp_v6_send_ack(sk, skb, tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
                        tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale,
                        tcp_tw_tsval(tcptw),
-                       tcptw->tw_ts_recent, tw->tw_bound_dev_if, &key,
-                       tw->tw_tclass, cpu_to_be32(tw->tw_flowlabel), tw->tw_priority,
-                       tw->tw_txhash);
+                       READ_ONCE(tcptw->tw_ts_recent), tw->tw_bound_dev_if,
+                       &key, tw->tw_tclass, cpu_to_be32(tw->tw_flowlabel),
+                       tw->tw_priority, tw->tw_txhash);
 
 #ifdef CONFIG_TCP_AO
 out: