From a9bf9c7dc6a5899c01cb8f6e773a66315a5cd4b7 Mon Sep 17 00:00:00 2001 From: Kuniyuki Iwashima Date: Tue, 4 Jun 2024 09:52:31 -0700 Subject: [PATCH] af_unix: Annotate data-race of sk->sk_state in unix_stream_connect(). As small optimisation, unix_stream_connect() prefetches the client's sk->sk_state without unix_state_lock() and checks if it's TCP_CLOSE. Later, sk->sk_state is checked again under unix_state_lock(). Let's use READ_ONCE() for the first check and TCP_CLOSE directly for the second check. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Kuniyuki Iwashima Signed-off-by: Paolo Abeni --- net/unix/af_unix.c | 7 ++----- 1 file changed, 2 insertions(+), 5 deletions(-) diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c index 3bacf47cb94d..84552826530d 100644 --- a/net/unix/af_unix.c +++ b/net/unix/af_unix.c @@ -1481,7 +1481,6 @@ static int unix_stream_connect(struct socket *sock, struct sockaddr *uaddr, struct sk_buff *skb = NULL; long timeo; int err; - int st; err = unix_validate_addr(sunaddr, addr_len); if (err) @@ -1571,9 +1570,7 @@ static int unix_stream_connect(struct socket *sock, struct sockaddr *uaddr, Well, and we have to recheck the state after socket locked. */ - st = sk->sk_state; - - switch (st) { + switch (READ_ONCE(sk->sk_state)) { case TCP_CLOSE: /* This is ok... continue with connect */ break; @@ -1588,7 +1585,7 @@ static int unix_stream_connect(struct socket *sock, struct sockaddr *uaddr, unix_state_lock_nested(sk, U_LOCK_SECOND); - if (sk->sk_state != st) { + if (sk->sk_state != TCP_CLOSE) { unix_state_unlock(sk); unix_state_unlock(other); sock_put(other);