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authorEric Dumazet <edumazet@google.com>2023-08-02 13:14:58 +0000
committerJakub Kicinski <kuba@kernel.org>2023-08-03 10:58:24 -0700
commit8c4d04f6b443869d25e59822f7cec88d647028a9 (patch)
treee6f680d01cd1850c178a1f308da251bb383258a3 /net/ipv4/tcp_metrics.c
parent285ce119a3c6c4502585936650143e54c8692788 (diff)
tcp_metrics: annotate data-races around tm->tcpm_vals[]
tm->tcpm_vals[] values can be read or written locklessly. Add needed READ_ONCE()/WRITE_ONCE() to document this, and force use of tcp_metric_get() and tcp_metric_set() Fixes: 51c5d0c4b169 ("tcp: Maintain dynamic metrics in local cache.") Signed-off-by: Eric Dumazet <edumazet@google.com> Reviewed-by: David Ahern <dsahern@kernel.org> Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net/ipv4/tcp_metrics.c')
-rw-r--r--net/ipv4/tcp_metrics.c23
1 files changed, 14 insertions, 9 deletions
diff --git a/net/ipv4/tcp_metrics.c b/net/ipv4/tcp_metrics.c
index 131fa3004969..fd4ab7a51cef 100644
--- a/net/ipv4/tcp_metrics.c
+++ b/net/ipv4/tcp_metrics.c
@@ -63,17 +63,19 @@ static bool tcp_metric_locked(struct tcp_metrics_block *tm,
return READ_ONCE(tm->tcpm_lock) & (1 << idx);
}
-static u32 tcp_metric_get(struct tcp_metrics_block *tm,
+static u32 tcp_metric_get(const struct tcp_metrics_block *tm,
enum tcp_metric_index idx)
{
- return tm->tcpm_vals[idx];
+ /* Paired with WRITE_ONCE() in tcp_metric_set() */
+ return READ_ONCE(tm->tcpm_vals[idx]);
}
static void tcp_metric_set(struct tcp_metrics_block *tm,
enum tcp_metric_index idx,
u32 val)
{
- tm->tcpm_vals[idx] = val;
+ /* Paired with READ_ONCE() in tcp_metric_get() */
+ WRITE_ONCE(tm->tcpm_vals[idx], val);
}
static bool addr_same(const struct inetpeer_addr *a,
@@ -115,13 +117,16 @@ static void tcpm_suck_dst(struct tcp_metrics_block *tm,
WRITE_ONCE(tm->tcpm_lock, val);
msval = dst_metric_raw(dst, RTAX_RTT);
- tm->tcpm_vals[TCP_METRIC_RTT] = msval * USEC_PER_MSEC;
+ tcp_metric_set(tm, TCP_METRIC_RTT, msval * USEC_PER_MSEC);
msval = dst_metric_raw(dst, RTAX_RTTVAR);
- tm->tcpm_vals[TCP_METRIC_RTTVAR] = msval * USEC_PER_MSEC;
- tm->tcpm_vals[TCP_METRIC_SSTHRESH] = dst_metric_raw(dst, RTAX_SSTHRESH);
- tm->tcpm_vals[TCP_METRIC_CWND] = dst_metric_raw(dst, RTAX_CWND);
- tm->tcpm_vals[TCP_METRIC_REORDERING] = dst_metric_raw(dst, RTAX_REORDERING);
+ tcp_metric_set(tm, TCP_METRIC_RTTVAR, msval * USEC_PER_MSEC);
+ tcp_metric_set(tm, TCP_METRIC_SSTHRESH,
+ dst_metric_raw(dst, RTAX_SSTHRESH));
+ tcp_metric_set(tm, TCP_METRIC_CWND,
+ dst_metric_raw(dst, RTAX_CWND));
+ tcp_metric_set(tm, TCP_METRIC_REORDERING,
+ dst_metric_raw(dst, RTAX_REORDERING));
if (fastopen_clear) {
tm->tcpm_fastopen.mss = 0;
tm->tcpm_fastopen.syn_loss = 0;
@@ -667,7 +672,7 @@ static int tcp_metrics_fill_info(struct sk_buff *msg,
if (!nest)
goto nla_put_failure;
for (i = 0; i < TCP_METRIC_MAX_KERNEL + 1; i++) {
- u32 val = tm->tcpm_vals[i];
+ u32 val = tcp_metric_get(tm, i);
if (!val)
continue;