From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 99365176AB0; Wed, 3 Jul 2024 10:49:24 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720003764; cv=none; b=R1uxAPBltMNLXWN7v+XaCKF9NBY7Ru+3xLzg/UlZXJ7jIUnkI5zoyIkmbv0MTp1mnN35nMxuHEEXmIhUk44Vev/xlwng5RivV4xyOFdgdDz7h/SWPMXaXn3mKxV1dF/QDWgjkf3ohywiQnMIoPh/X+M9njhrSZijlo8FUl7b0TI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720003764; c=relaxed/simple; bh=HQZ8pu5C/+mo3pwHhpK8EGdA9NrTbROFoBN+ZhaCN/M=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=MLG2KR/x6xQP0N595qbkj8HQfOFWk7ZI1jqAATW1wcGrEpvAF32HabVaw/W2ii3Dc0Qj3RuQhJYB5zGvoIHfWJP7Mv1AREhfoVfkhjZTzXSY7znMDoF+wYGNww92jGURHT231ZztpWEgpUvFJLfD/CJ25sPUnC0MqMnLq3LVvJo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=oEKzdDFL; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="oEKzdDFL" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1AE2DC2BD10; Wed, 3 Jul 2024 10:49:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1720003764; bh=HQZ8pu5C/+mo3pwHhpK8EGdA9NrTbROFoBN+ZhaCN/M=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=oEKzdDFLFuQAD8V35B0CwjIwxpkzR4PIB7aWIcos6muryh2GzcIBeVRzJawOSTRtJ EQ4z2/7CCh5cePZnAFrMnwuZo1JUX/YHqUhRTYmtrFjZRrAYNT5HtkG/qZi4RGblKG iPcLm53W2dRY5fSJbP0vZNKVqf14ZHw7mSUCSgbQ= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Kuniyuki Iwashima , Paolo Abeni , Sasha Levin Subject: [PATCH 5.4 015/189] af_unix: Annotate data-races around sk->sk_state in unix_write_space() and poll(). Date: Wed, 3 Jul 2024 12:37:56 +0200 Message-ID: <20240703102842.079406072@linuxfoundation.org> X-Mailer: git-send-email 2.45.2 In-Reply-To: <20240703102841.492044697@linuxfoundation.org> References: <20240703102841.492044697@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Kuniyuki Iwashima [ Upstream commit eb0718fb3e97ad0d6f4529b810103451c90adf94 ] unix_poll() and unix_dgram_poll() read sk->sk_state locklessly and calls unix_writable() which also reads sk->sk_state without holding unix_state_lock(). Let's use READ_ONCE() in unix_poll() and unix_dgram_poll() and pass it to unix_writable(). While at it, we remove TCP_SYN_SENT check in unix_dgram_poll() as that state does not exist for AF_UNIX socket since the code was added. Fixes: 1586a5877db9 ("af_unix: do not report POLLOUT on listeners") Fixes: 3c73419c09a5 ("af_unix: fix 'poll for write'/ connected DGRAM sockets") Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Kuniyuki Iwashima Signed-off-by: Paolo Abeni Signed-off-by: Sasha Levin --- net/unix/af_unix.c | 25 ++++++++++++------------- 1 file changed, 12 insertions(+), 13 deletions(-) diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c index 8ab1e2a781195..73cc992bed880 100644 --- a/net/unix/af_unix.c +++ b/net/unix/af_unix.c @@ -449,9 +449,9 @@ static int unix_dgram_peer_wake_me(struct sock *sk, struct sock *other) return 0; } -static int unix_writable(const struct sock *sk) +static int unix_writable(const struct sock *sk, unsigned char state) { - return sk->sk_state != TCP_LISTEN && + return state != TCP_LISTEN && (refcount_read(&sk->sk_wmem_alloc) << 2) <= sk->sk_sndbuf; } @@ -460,7 +460,7 @@ static void unix_write_space(struct sock *sk) struct socket_wq *wq; rcu_read_lock(); - if (unix_writable(sk)) { + if (unix_writable(sk, READ_ONCE(sk->sk_state))) { wq = rcu_dereference(sk->sk_wq); if (skwq_has_sleeper(wq)) wake_up_interruptible_sync_poll(&wq->wait, @@ -2678,12 +2678,14 @@ static int unix_compat_ioctl(struct socket *sock, unsigned int cmd, unsigned lon static __poll_t unix_poll(struct file *file, struct socket *sock, poll_table *wait) { struct sock *sk = sock->sk; + unsigned char state; __poll_t mask; u8 shutdown; sock_poll_wait(file, sock, wait); mask = 0; shutdown = READ_ONCE(sk->sk_shutdown); + state = READ_ONCE(sk->sk_state); /* exceptional events? */ if (sk->sk_err) @@ -2699,14 +2701,14 @@ static __poll_t unix_poll(struct file *file, struct socket *sock, poll_table *wa /* Connection-based need to check for termination and startup */ if ((sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET) && - sk->sk_state == TCP_CLOSE) + state == TCP_CLOSE) mask |= EPOLLHUP; /* * we set writable also when the other side has shut down the * connection. This prevents stuck sockets. */ - if (unix_writable(sk)) + if (unix_writable(sk, state)) mask |= EPOLLOUT | EPOLLWRNORM | EPOLLWRBAND; return mask; @@ -2717,12 +2719,14 @@ static __poll_t unix_dgram_poll(struct file *file, struct socket *sock, { struct sock *sk = sock->sk, *other; unsigned int writable; + unsigned char state; __poll_t mask; u8 shutdown; sock_poll_wait(file, sock, wait); mask = 0; shutdown = READ_ONCE(sk->sk_shutdown); + state = READ_ONCE(sk->sk_state); /* exceptional events? */ if (sk->sk_err || !skb_queue_empty_lockless(&sk->sk_error_queue)) @@ -2739,19 +2743,14 @@ static __poll_t unix_dgram_poll(struct file *file, struct socket *sock, mask |= EPOLLIN | EPOLLRDNORM; /* Connection-based need to check for termination and startup */ - if (sk->sk_type == SOCK_SEQPACKET) { - if (sk->sk_state == TCP_CLOSE) - mask |= EPOLLHUP; - /* connection hasn't started yet? */ - if (sk->sk_state == TCP_SYN_SENT) - return mask; - } + if (sk->sk_type == SOCK_SEQPACKET && state == TCP_CLOSE) + mask |= EPOLLHUP; /* No write status requested, avoid expensive OUT tests. */ if (!(poll_requested_events(wait) & (EPOLLWRBAND|EPOLLWRNORM|EPOLLOUT))) return mask; - writable = unix_writable(sk); + writable = unix_writable(sk, state); if (writable) { unix_state_lock(sk); -- 2.43.0