From 285975dd674258ccb33e77a1803e8f2015e67105 Mon Sep 17 00:00:00 2001
From: Eric Dumazet <edumazet@google.com>
Date: Fri, 28 Jul 2023 15:03:12 +0000
Subject: [PATCH] net: annotate data-races around sk->sk_{rcv|snd}timeo
sk_getsockopt() runs without locks, we must add annotations
to sk->sk_rcvtimeo and sk->sk_sndtimeo.
In the future we might allow fetching these fields before
we lock the socket in TCP fast path.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
net/core/sock.c | 24 ++++++++++++++----------
net/sched/em_meta.c | 4 ++--
2 files changed, 16 insertions(+), 12 deletions(-)
diff --git a/net/core/sock.c b/net/core/sock.c
index 08e6050016057..264c99c190ac9 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -429,6 +429,7 @@ static int sock_set_timeout(long *timeo_p, sockptr_t optval, int optlen,
{
struct __kernel_sock_timeval tv;
int err = sock_copy_user_timeval(&tv, optval, optlen, old_timeval);
+ long val;
if (err)
return err;
@@ -439,7 +440,7 @@ static int sock_set_timeout(long *timeo_p, sockptr_t optval, int optlen,
if (tv.tv_sec < 0) {
static int warned __read_mostly;
- *timeo_p = 0;
+ WRITE_ONCE(*timeo_p, 0);
if (warned < 10 && net_ratelimit()) {
warned++;
pr_info("%s: `%s' (pid %d) tries to set negative timeout\n",
@@ -447,11 +448,12 @@ static int sock_set_timeout(long *timeo_p, sockptr_t optval, int optlen,
}
return 0;
}
- *timeo_p = MAX_SCHEDULE_TIMEOUT;
- if (tv.tv_sec == 0 && tv.tv_usec == 0)
- return 0;
- if (tv.tv_sec < (MAX_SCHEDULE_TIMEOUT / HZ - 1))
- *timeo_p = tv.tv_sec * HZ + DIV_ROUND_UP((unsigned long)tv.tv_usec, USEC_PER_SEC / HZ);
+ val = MAX_SCHEDULE_TIMEOUT;
+ if ((tv.tv_sec || tv.tv_usec) &&
+ (tv.tv_sec < (MAX_SCHEDULE_TIMEOUT / HZ - 1)))
+ val = tv.tv_sec * HZ + DIV_ROUND_UP((unsigned long)tv.tv_usec,
+ USEC_PER_SEC / HZ);
+ WRITE_ONCE(*timeo_p, val);
return 0;
}
@@ -813,9 +815,9 @@ void sock_set_sndtimeo(struct sock *sk, s64 secs)
{
lock_sock(sk);
if (secs && secs < MAX_SCHEDULE_TIMEOUT / HZ - 1)
- sk->sk_sndtimeo = secs * HZ;
+ WRITE_ONCE(sk->sk_sndtimeo, secs * HZ);
else
- sk->sk_sndtimeo = MAX_SCHEDULE_TIMEOUT;
+ WRITE_ONCE(sk->sk_sndtimeo, MAX_SCHEDULE_TIMEOUT);
release_sock(sk);
}
EXPORT_SYMBOL(sock_set_sndtimeo);
@@ -1721,12 +1723,14 @@ int sk_getsockopt(struct sock *sk, int level, int optname,
case SO_RCVTIMEO_OLD:
case SO_RCVTIMEO_NEW:
- lv = sock_get_timeout(sk->sk_rcvtimeo, &v, SO_RCVTIMEO_OLD == optname);
+ lv = sock_get_timeout(READ_ONCE(sk->sk_rcvtimeo), &v,
+ SO_RCVTIMEO_OLD == optname);
break;
case SO_SNDTIMEO_OLD:
case SO_SNDTIMEO_NEW:
- lv = sock_get_timeout(sk->sk_sndtimeo, &v, SO_SNDTIMEO_OLD == optname);
+ lv = sock_get_timeout(READ_ONCE(sk->sk_sndtimeo), &v,
+ SO_SNDTIMEO_OLD == optname);
break;
case SO_RCVLOWAT:
diff --git a/net/sched/em_meta.c b/net/sched/em_meta.c
index af85a73c4c545..6fdba069f6bfd 100644
--- a/net/sched/em_meta.c
+++ b/net/sched/em_meta.c
@@ -568,7 +568,7 @@ META_COLLECTOR(int_sk_rcvtimeo)
*err = -1;
return;
}
- dst->value = sk->sk_rcvtimeo / HZ;
+ dst->value = READ_ONCE(sk->sk_rcvtimeo) / HZ;
}
META_COLLECTOR(int_sk_sndtimeo)
@@ -579,7 +579,7 @@ META_COLLECTOR(int_sk_sndtimeo)
*err = -1;
return;
}
- dst->value = sk->sk_sndtimeo / HZ;
+ dst->value = READ_ONCE(sk->sk_sndtimeo) / HZ;
}
META_COLLECTOR(int_sk_sendmsg_off)