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tcp: annotate data-races around tp->notsent_lowat 

tp->notsent_lowat can be read locklessly from do_tcp_getsockopt()
and tcp_poll().

Fixes: c9bee3b7fd ("tcp: TCP_NOTSENT_LOWAT socket option")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Link: https://lore.kernel.org/r/20230719212857.3943972-10-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Eric Dumazet 2023-07-19 21:28:55 +00:00 committed by Jakub Kicinski
parent ae488c7442
commit 1aeb87bc14
2 changed files with 7 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
include/net/tcp.h
View File

@ -2061,7 +2061,11 @@ void __tcp_v4_send_check(struct sk_buff *skb, __be32 saddr, __be32 daddr);
static inline u32 tcp_notsent_lowat(const struct tcp_sock *tp)
{
struct net *net = sock_net((struct sock *)tp);
return tp->notsent_lowat ?: READ_ONCE(net->ipv4.sysctl_tcp_notsent_lowat);
u32 val;
val = READ_ONCE(tp->notsent_lowat);
return val ?: READ_ONCE(net->ipv4.sysctl_tcp_notsent_lowat);
}
bool tcp_stream_memory_free(const struct sock *sk, int wake);

4
net/ipv4/tcp.c
View File

@ -3664,7 +3664,7 @@ int do_tcp_setsockopt(struct sock *sk, int level, int optname,
err = tcp_repair_set_window(tp, optval, optlen);
break;
case TCP_NOTSENT_LOWAT:
tp->notsent_lowat = val;
WRITE_ONCE(tp->notsent_lowat, val);
sk->sk_write_space(sk);
break;
case TCP_INQ:
@ -4164,7 +4164,7 @@ int do_tcp_getsockopt(struct sock *sk, int level,
val = tcp_time_stamp_raw() + READ_ONCE(tp->tsoffset);
break;
case TCP_NOTSENT_LOWAT:
val = tp->notsent_lowat;
val = READ_ONCE(tp->notsent_lowat);
break;
case TCP_INQ:
val = tp->recvmsg_inq;