From c7ebe08f4081fe69c719c5690c3211d125f625b6 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Fri, 28 Jul 2023 15:03:10 +0000 Subject: [PATCH] net: annotate data-races around sk->sk_max_pacing_rate [ Upstream commit ea7f45ef77b39e72244d282e47f6cb1ef4135cd2 ] sk_getsockopt() runs locklessly. This means sk->sk_max_pacing_rate can be read while other threads are changing its value. Fixes: 62748f32d501 ("net: introduce SO_MAX_PACING_RATE") Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- net/core/sock.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/net/core/sock.c b/net/core/sock.c index 4e00c6e2cb43..c7ba7d82eb36 100644 --- a/net/core/sock.c +++ b/net/core/sock.c @@ -1183,7 +1183,8 @@ set_sndbuf: cmpxchg(&sk->sk_pacing_status, SK_PACING_NONE, SK_PACING_NEEDED); - sk->sk_max_pacing_rate = ulval; + /* Pairs with READ_ONCE() from sk_getsockopt() */ + WRITE_ONCE(sk->sk_max_pacing_rate, ulval); sk->sk_pacing_rate = min(sk->sk_pacing_rate, ulval); break; } @@ -1551,12 +1552,14 @@ int sock_getsockopt(struct socket *sock, int level, int optname, #endif case SO_MAX_PACING_RATE: + /* The READ_ONCE() pair with the WRITE_ONCE() in sk_setsockopt() */ if (sizeof(v.ulval) != sizeof(v.val) && len >= sizeof(v.ulval)) { lv = sizeof(v.ulval); - v.ulval = sk->sk_max_pacing_rate; + v.ulval = READ_ONCE(sk->sk_max_pacing_rate); } else { /* 32bit version */ - v.val = min_t(unsigned long, sk->sk_max_pacing_rate, ~0U); + v.val = min_t(unsigned long, ~0U, + READ_ONCE(sk->sk_max_pacing_rate)); } break;