From: Eric Dumazet <edumazet@xxxxxxxxxx>
[ Upstream commit 348b81b68b13ebd489a3e6a46aa1c384c731c919 ]
do_tcp_getsockopt() reads tp->tcp_tx_delay while another cpu
might change its value.
Fixes: a842fe1425cb ("tcp: add optional per socket transmit delay")
Signed-off-by: Eric Dumazet <edumazet@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20230719212857.3943972-2-edumazet@xxxxxxxxxx
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
net/ipv4/tcp.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index cc42ceadc1127..39919d1436cea 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -3447,7 +3447,7 @@ static int do_tcp_setsockopt(struct sock *sk, int level, int optname,
case TCP_TX_DELAY:
if (val)
tcp_enable_tx_delay();
- tp->tcp_tx_delay = val;
+ WRITE_ONCE(tp->tcp_tx_delay, val);
break;
default:
err = -ENOPROTOOPT;
@@ -3902,7 +3902,7 @@ static int do_tcp_getsockopt(struct sock *sk, int level,
break;
case TCP_TX_DELAY:
- val = tp->tcp_tx_delay;
+ val = READ_ONCE(tp->tcp_tx_delay);
break;
case TCP_TIMESTAMP:
--
2.39.2
