[PATCH v2 net 05/15] af_unix: Annotate data-race of sk->sk_state in unix_stream_connect().
From: Kuniyuki Iwashima <hidden>
Date: 2024-06-04 16:54:57
Subsystem:
networking [general], networking [unix sockets], the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Kuniyuki Iwashima, Linus Torvalds
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 <redacted>
---
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);
--
2.30.2