From nobody Mon Feb 9 00:10:13 2026 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (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 C602F5392 for ; Thu, 26 Jan 2023 21:05:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1674767142; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=8Q00Z4Trst2e3TeHPJUTeBUPj/W8TtHliQ41m22Xlsc=; b=SprOmql9TsdbZa6usgX7WFchKD00RXnqacAclGvLrURAVrjJ4maFcE/KX1FjSBPj21hSE2 2Doylkf1cBs5egpdek3VbOoa9xT2tWqKopUsnAda0E3K6dJEW0ch30HenyH7o0oWZ/Mcgt +r0stFVdYq2B3lZmIF4Adokjy2Ov9Zk= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-288-Kq6LH1dKMCW0QE7nZkJ2KA-1; Thu, 26 Jan 2023 16:05:41 -0500 X-MC-Unique: Kq6LH1dKMCW0QE7nZkJ2KA-1 Received: from smtp.corp.redhat.com (int-mx09.intmail.prod.int.rdu2.redhat.com [10.11.54.9]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 0BEA2857A86 for ; Thu, 26 Jan 2023 21:05:41 +0000 (UTC) Received: from gerbillo.redhat.com (unknown [10.39.192.60]) by smtp.corp.redhat.com (Postfix) with ESMTP id 94672492C18 for ; Thu, 26 Jan 2023 21:05:40 +0000 (UTC) From: Paolo Abeni To: mptcp@lists.linux.dev Subject: [PATCH v3 mptcp-next 02/15] mptcp: fix locking for setsockopt corner-case Date: Thu, 26 Jan 2023 22:05:07 +0100 Message-Id: <0d9c9eb3fac78843df8c62e287e9e2a11fabfcdc.1674767058.git.pabeni@redhat.com> In-Reply-To: References: Precedence: bulk X-Mailing-List: mptcp@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.9 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8"; x-default="true" We need to call the __mptcp_nmpc_socket(), and later subflow socket access under the msk socket lock, or e.g. a racing connect() could change the socket status under the wood, with unexpected results. Fixes: 54635bd04701 ("mptcp: add TCP_FASTOPEN_CONNECT socket option") Signed-off-by: Paolo Abeni --- this and the next patch are new v2. In both case the addressed issue is almost irrelevant until patch 8/12, but will cause lockdep splat after such change --- net/mptcp/sockopt.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/net/mptcp/sockopt.c b/net/mptcp/sockopt.c index 9986681aaf40..8a9656248b0f 100644 --- a/net/mptcp/sockopt.c +++ b/net/mptcp/sockopt.c @@ -760,14 +760,21 @@ static int mptcp_setsockopt_v4(struct mptcp_sock *msk= , int optname, static int mptcp_setsockopt_first_sf_only(struct mptcp_sock *msk, int leve= l, int optname, sockptr_t optval, unsigned int optlen) { + struct sock *sk =3D (struct sock *)msk; struct socket *sock; + int ret =3D -EINVAL; =20 /* Limit to first subflow, before the connection establishment */ + lock_sock(sk); sock =3D __mptcp_nmpc_socket(msk); if (!sock) - return -EINVAL; + goto unlock; =20 - return tcp_setsockopt(sock->sk, level, optname, optval, optlen); + ret =3D tcp_setsockopt(sock->sk, level, optname, optval, optlen); + +unlock: + release_sock(sk); + return ret; } =20 static int mptcp_setsockopt_sol_tcp(struct mptcp_sock *msk, int optname, --=20 2.39.1