From: Eric Dumazet edumazet@google.com
[ Upstream commit c76a0328899bbe226f8adeb88b8da9e4167bd316 ]
sk_getsockopt() runs locklessly. This means sk->sk_txrehash can be read while other threads are changing its value.
Other locations were handled in commit cb6cd2cec799 ("tcp: Change SYN ACK retransmit behaviour to account for rehash")
Fixes: 26859240e4ee ("txhash: Add socket option to control TX hash rethink behavior") Signed-off-by: Eric Dumazet edumazet@google.com Cc: Akhmat Karakotov hmukos@yandex-team.ru Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Sasha Levin sashal@kernel.org --- net/core/sock.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/net/core/sock.c b/net/core/sock.c index 7b88290ddc6e7..b25511e7e8103 100644 --- a/net/core/sock.c +++ b/net/core/sock.c @@ -1523,7 +1523,9 @@ int sk_setsockopt(struct sock *sk, int level, int optname, } if ((u8)val == SOCK_TXREHASH_DEFAULT) val = READ_ONCE(sock_net(sk)->core.sysctl_txrehash); - /* Paired with READ_ONCE() in tcp_rtx_synack() */ + /* Paired with READ_ONCE() in tcp_rtx_synack() + * and sk_getsockopt(). + */ WRITE_ONCE(sk->sk_txrehash, (u8)val); break;
@@ -1930,7 +1932,8 @@ int sk_getsockopt(struct sock *sk, int level, int optname, break;
case SO_TXREHASH: - v.val = sk->sk_txrehash; + /* Paired with WRITE_ONCE() in sk_setsockopt() */ + v.val = READ_ONCE(sk->sk_txrehash); break;
default: