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 20137611B for ; Sun, 28 May 2023 19:39:23 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9F5B6C433D2; Sun, 28 May 2023 19:39:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1685302763; bh=Bq/AU4cAh2jQwdWY4JZ2sXmLsnVduMCvzpVmMJi0LuI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=yGjKaiazciw7VVrlsBMx6hMj66k4S9iZ/a5P1rAMsueybyue7hr1f3B1CiMUslrOZ K1Dpw58OJIXiRTj16RF0E5JDOa3Y2BElF9+lwFvAxe2UPR+/j7wfAU35JTjfEQpwv1 s0mg2quH9WR/yOlMSDLLt6GkPHZYJShQzuoth/aQ= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Eric Dumazet , Kuniyuki Iwashima , Jakub Kicinski , Sasha Levin Subject: [PATCH 5.10 016/211] net: datagram: fix data-races in datagram_poll() Date: Sun, 28 May 2023 20:08:57 +0100 Message-Id: <20230528190843.930293991@linuxfoundation.org> X-Mailer: git-send-email 2.40.1 In-Reply-To: <20230528190843.514829708@linuxfoundation.org> References: <20230528190843.514829708@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Eric Dumazet [ Upstream commit 5bca1d081f44c9443e61841842ce4e9179d327b6 ] datagram_poll() runs locklessly, we should add READ_ONCE() annotations while reading sk->sk_err, sk->sk_shutdown and sk->sk_state. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Eric Dumazet Reviewed-by: Kuniyuki Iwashima Link: https://lore.kernel.org/r/20230509173131.3263780-1-edumazet@google.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- net/core/datagram.c | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-) diff --git a/net/core/datagram.c b/net/core/datagram.c index bc92683fdcdb4..9e77695d1bdc2 100644 --- a/net/core/datagram.c +++ b/net/core/datagram.c @@ -799,18 +799,21 @@ __poll_t datagram_poll(struct file *file, struct socket *sock, { struct sock *sk = sock->sk; __poll_t mask; + u8 shutdown; sock_poll_wait(file, sock, wait); mask = 0; /* exceptional events? */ - if (sk->sk_err || !skb_queue_empty_lockless(&sk->sk_error_queue)) + if (READ_ONCE(sk->sk_err) || + !skb_queue_empty_lockless(&sk->sk_error_queue)) mask |= EPOLLERR | (sock_flag(sk, SOCK_SELECT_ERR_QUEUE) ? EPOLLPRI : 0); - if (sk->sk_shutdown & RCV_SHUTDOWN) + shutdown = READ_ONCE(sk->sk_shutdown); + if (shutdown & RCV_SHUTDOWN) mask |= EPOLLRDHUP | EPOLLIN | EPOLLRDNORM; - if (sk->sk_shutdown == SHUTDOWN_MASK) + if (shutdown == SHUTDOWN_MASK) mask |= EPOLLHUP; /* readable? */ @@ -819,10 +822,12 @@ __poll_t datagram_poll(struct file *file, struct socket *sock, /* Connection-based need to check for termination and startup */ if (connection_based(sk)) { - if (sk->sk_state == TCP_CLOSE) + int state = READ_ONCE(sk->sk_state); + + if (state == TCP_CLOSE) mask |= EPOLLHUP; /* connection hasn't started yet? */ - if (sk->sk_state == TCP_SYN_SENT) + if (state == TCP_SYN_SENT) return mask; } -- 2.39.2