diff options
| -rw-r--r-- | include/net/tcp.h | 10 | ||||
| -rw-r--r-- | net/ipv4/tcp.c | 14 |
2 files changed, 17 insertions, 7 deletions
diff --git a/include/net/tcp.h b/include/net/tcp.h index dfa52ceefd23..674af493882c 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -2208,10 +2208,14 @@ static inline void tcp_chrono_set(struct tcp_sock *tp, const enum tcp_chrono new const u32 now = tcp_jiffies32; enum tcp_chrono old = tp->chrono_type; + /* Following WRITE_ONCE()s pair with READ_ONCE()s in + * tcp_get_info_chrono_stats(). + */ if (old > TCP_CHRONO_UNSPEC) - tp->chrono_stat[old - 1] += now - tp->chrono_start; - tp->chrono_start = now; - tp->chrono_type = new; + WRITE_ONCE(tp->chrono_stat[old - 1], + tp->chrono_stat[old - 1] + now - tp->chrono_start); + WRITE_ONCE(tp->chrono_start, now); + WRITE_ONCE(tp->chrono_type, new); } static inline void tcp_chrono_start(struct sock *sk, const enum tcp_chrono type) diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index 1a494d18c5fd..7b7812cb710f 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -4191,12 +4191,18 @@ static void tcp_get_info_chrono_stats(const struct tcp_sock *tp, struct tcp_info *info) { u64 stats[__TCP_CHRONO_MAX], total = 0; - enum tcp_chrono i; + enum tcp_chrono i, cur; + /* Following READ_ONCE()s pair with WRITE_ONCE()s in tcp_chrono_set(). + * This is because socket lock might not be owned by us at this point. + * This is best effort, tcp_get_timestamping_opt_stats() can + * see wrong values. A real fix would be too costly for TCP fast path. + */ + cur = READ_ONCE(tp->chrono_type); for (i = TCP_CHRONO_BUSY; i < __TCP_CHRONO_MAX; ++i) { - stats[i] = tp->chrono_stat[i - 1]; - if (i == tp->chrono_type) - stats[i] += tcp_jiffies32 - tp->chrono_start; + stats[i] = READ_ONCE(tp->chrono_stat[i - 1]); + if (i == cur) + stats[i] += tcp_jiffies32 - READ_ONCE(tp->chrono_start); stats[i] *= USEC_PER_SEC / HZ; total += stats[i]; } |