From patchwork Thu Aug 12 05:30:56 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Longpeng(Mike)" X-Patchwork-Id: 12432511 X-Patchwork-Delegate: kuba@kernel.org Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8F633C4338F for ; Thu, 12 Aug 2021 05:31:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 71BE760241 for ; Thu, 12 Aug 2021 05:31:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234350AbhHLFbj (ORCPT ); Thu, 12 Aug 2021 01:31:39 -0400 Received: from szxga03-in.huawei.com ([45.249.212.189]:13308 "EHLO szxga03-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234315AbhHLFbh (ORCPT ); Thu, 12 Aug 2021 01:31:37 -0400 Received: from dggemv704-chm.china.huawei.com (unknown [172.30.72.57]) by szxga03-in.huawei.com (SkyGuard) with ESMTP id 4GlZsp2Nv4z7tJV; Thu, 12 Aug 2021 13:26:06 +0800 (CST) Received: from dggpeml500016.china.huawei.com (7.185.36.70) by dggemv704-chm.china.huawei.com (10.3.19.47) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2176.2; Thu, 12 Aug 2021 13:31:05 +0800 Received: from DESKTOP-27KDQMV.china.huawei.com (10.174.148.223) by dggpeml500016.china.huawei.com (7.185.36.70) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2176.2; Thu, 12 Aug 2021 13:31:05 +0800 From: "Longpeng(Mike)" To: CC: , , , , , "Longpeng(Mike)" , Stefan Hajnoczi , "David S. Miller" , Jakub Kicinski Subject: [PATCH resend] vsock/virtio: avoid potential deadlock when vsock device remove Date: Thu, 12 Aug 2021 13:30:56 +0800 Message-ID: <20210812053056.1699-1-longpeng2@huawei.com> X-Mailer: git-send-email 2.25.0.windows.1 MIME-Version: 1.0 X-Originating-IP: [10.174.148.223] X-ClientProxiedBy: dggems702-chm.china.huawei.com (10.3.19.179) To dggpeml500016.china.huawei.com (7.185.36.70) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org There's a potential deadlock case when remove the vsock device or process the RESET event: vsock_for_each_connected_socket: spin_lock_bh(&vsock_table_lock) ----------- (1) ... virtio_vsock_reset_sock: lock_sock(sk) --------------------- (2) ... spin_unlock_bh(&vsock_table_lock) lock_sock() may do initiative schedule when the 'sk' is owned by other thread at the same time, we would receivce a warning message that "scheduling while atomic". Even worse, if the next task (selected by the scheduler) try to release a 'sk', it need to request vsock_table_lock and the deadlock occur, cause the system into softlockup state. Call trace: queued_spin_lock_slowpath vsock_remove_bound vsock_remove_sock virtio_transport_release __vsock_release vsock_release __sock_release sock_close __fput ____fput So we should not require sk_lock in this case, just like the behavior in vhost_vsock or vmci. Cc: Stefan Hajnoczi Cc: Stefano Garzarella Cc: "David S. Miller" Cc: Jakub Kicinski Signed-off-by: Longpeng(Mike) Reviewed-by: Stefano Garzarella --- net/vmw_vsock/virtio_transport.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/net/vmw_vsock/virtio_transport.c b/net/vmw_vsock/virtio_transport.c index e0c2c99..4f7c99d 100644 --- a/net/vmw_vsock/virtio_transport.c +++ b/net/vmw_vsock/virtio_transport.c @@ -357,11 +357,14 @@ static void virtio_vsock_event_fill(struct virtio_vsock *vsock) static void virtio_vsock_reset_sock(struct sock *sk) { - lock_sock(sk); + /* vmci_transport.c doesn't take sk_lock here either. At least we're + * under vsock_table_lock so the sock cannot disappear while we're + * executing. + */ + sk->sk_state = TCP_CLOSE; sk->sk_err = ECONNRESET; sk_error_report(sk); - release_sock(sk); } static void virtio_vsock_update_guest_cid(struct virtio_vsock *vsock)