From 83690b82d228b3570565ebd0b41873933238b97f Mon Sep 17 00:00:00 2001
From: Kuniyuki Iwashima <kuniyu@amazon.com>
Date: Tue, 4 Jun 2024 09:52:39 -0700
Subject: [PATCH] af_unix: Use skb_queue_empty_lockless() in
unix_release_sock().
If the socket type is SOCK_STREAM or SOCK_SEQPACKET, unix_release_sock()
checks the length of the peer socket's recvq under unix_state_lock().
However, unix_stream_read_generic() calls skb_unlink() after releasing
the lock. Also, for SOCK_SEQPACKET, __skb_try_recv_datagram() unlinks
skb without unix_state_lock().
Thues, unix_state_lock() does not protect qlen.
Let's use skb_queue_empty_lockless() in unix_release_sock().
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
---
net/unix/af_unix.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
index eb3ba3448ed34..80846279de9f3 100644
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -631,7 +631,7 @@ static void unix_release_sock(struct sock *sk, int embrion)
unix_state_lock(skpair);
/* No more writes */
WRITE_ONCE(skpair->sk_shutdown, SHUTDOWN_MASK);
- if (!skb_queue_empty(&sk->sk_receive_queue) || embrion)
+ if (!skb_queue_empty_lockless(&sk->sk_receive_queue) || embrion)
WRITE_ONCE(skpair->sk_err, ECONNRESET);
unix_state_unlock(skpair);
skpair->sk_state_change(skpair);
--
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