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tcp_metrics: annotate data-races around tm->tcpm_vals[]

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[ Upstream commit 8c4d04f6b443869d25e59822f7cec88d647028a9 ]

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: 51c5d0c4b1 ("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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Eric Dumazet
2023-08-02 13:14:58 +00:00
committed by Greg Kroah-Hartman
parent 57bcbbb208
commit 079afb1815
1 changed files with 14 additions and 9 deletions
Download Patch File Download Diff File Expand all files Collapse all files

23
net/ipv4/tcp_metrics.c
View File

@@ -63,17 +63,19 @@ static bool tcp_metric_locked(struct tcp_metrics_block *tm,
return READ_ONCE(tm->tcpm_lock) & (1 << idx); 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) 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, static void tcp_metric_set(struct tcp_metrics_block *tm,
enum tcp_metric_index idx, enum tcp_metric_index idx,
u32 val) 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, 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); WRITE_ONCE(tm->tcpm_lock, val);
msval = dst_metric_raw(dst, RTAX_RTT); 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); msval = dst_metric_raw(dst, RTAX_RTTVAR);
tm->tcpm_vals[TCP_METRIC_RTTVAR] = msval * USEC_PER_MSEC; tcp_metric_set(tm, TCP_METRIC_RTTVAR, msval * USEC_PER_MSEC);
tm->tcpm_vals[TCP_METRIC_SSTHRESH] = dst_metric_raw(dst, RTAX_SSTHRESH); tcp_metric_set(tm, TCP_METRIC_SSTHRESH,
tm->tcpm_vals[TCP_METRIC_CWND] = dst_metric_raw(dst, RTAX_CWND); dst_metric_raw(dst, RTAX_SSTHRESH));
tm->tcpm_vals[TCP_METRIC_REORDERING] = dst_metric_raw(dst, RTAX_REORDERING); 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) { if (fastopen_clear) {
tm->tcpm_fastopen.mss = 0; tm->tcpm_fastopen.mss = 0;
tm->tcpm_fastopen.syn_loss = 0; tm->tcpm_fastopen.syn_loss = 0;
@@ -667,7 +672,7 @@ static int tcp_metrics_fill_info(struct sk_buff *msg,
if (!nest) if (!nest)
goto nla_put_failure; goto nla_put_failure;
for (i = 0; i < TCP_METRIC_MAX_KERNEL + 1; i++) { 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) if (!val)
continue; continue;