From: Eric Dumazet <edumazet@xxxxxxxxxx>
[ Upstream commit 9df5335ca974e688389c875546e5819778a80d59 ]
do_tcp_getsockopt() reads tp->linger2 while another cpu
might change its value.
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Eric Dumazet <edumazet@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20230719212857.3943972-8-edumazet@xxxxxxxxxx
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
net/ipv4/tcp.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index ffa9717293358..363535b6ece83 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -3691,11 +3691,11 @@ int do_tcp_setsockopt(struct sock *sk, int level, int optname,
case TCP_LINGER2:
if (val < 0)
- tp->linger2 = -1;
+ WRITE_ONCE(tp->linger2, -1);
else if (val > TCP_FIN_TIMEOUT_MAX / HZ)
- tp->linger2 = TCP_FIN_TIMEOUT_MAX;
+ WRITE_ONCE(tp->linger2, TCP_FIN_TIMEOUT_MAX);
else
- tp->linger2 = val * HZ;
+ WRITE_ONCE(tp->linger2, val * HZ);
break;
case TCP_DEFER_ACCEPT:
@@ -4099,7 +4099,7 @@ int do_tcp_getsockopt(struct sock *sk, int level,
READ_ONCE(net->ipv4.sysctl_tcp_syn_retries);
break;
case TCP_LINGER2:
- val = tp->linger2;
+ val = READ_ONCE(tp->linger2);
if (val >= 0)
val = (val ? : READ_ONCE(net->ipv4.sysctl_tcp_fin_timeout)) / HZ;
break;
--
2.39.2
