From mboxrd@z Thu Jan 1 00:00:00 1970 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=-19.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 9DD96C4320A for ; Mon, 16 Aug 2021 13:16:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 89B36632A3 for ; Mon, 16 Aug 2021 13:16:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240417AbhHPNQs (ORCPT ); Mon, 16 Aug 2021 09:16:48 -0400 Received: from mail.kernel.org ([198.145.29.99]:56748 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237818AbhHPNJN (ORCPT ); Mon, 16 Aug 2021 09:09:13 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id E190A6115A; Mon, 16 Aug 2021 13:08:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1629119294; bh=k0E4IpDlHZyHchq2thmJAO7kY8pZrnFMSqqJPmaNis8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=AXTW0dduDAjOr0LZCLelFETx3oCis96U9fAyrfJAb9zfm0VJwxigNeg9wakGVqPY6 X7d2Y95kVntmHjBMS5IJjjnmrt04ZPebPSnNBOm7ZOB+aQEhAZkdPqte7nr2iUp21A K5EMpFwTKbquZAcfaNPtdK6M9h/bEiW+uN/4idoo= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Stefan Hajnoczi , "Longpeng(Mike)" , Stefano Garzarella , Jakub Kicinski , Sasha Levin Subject: [PATCH 5.10 66/96] vsock/virtio: avoid potential deadlock when vsock device remove Date: Mon, 16 Aug 2021 15:02:16 +0200 Message-Id: <20210816125437.158517633@linuxfoundation.org> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210816125434.948010115@linuxfoundation.org> References: <20210816125434.948010115@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Longpeng(Mike) [ Upstream commit 49b0b6ffe20c5344f4173f3436298782a08da4f2 ] 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. Fixes: 0ea9e1d3a9e3 ("VSOCK: Introduce virtio_transport.ko") Cc: Stefan Hajnoczi Signed-off-by: Longpeng(Mike) Reviewed-by: Stefano Garzarella Link: https://lore.kernel.org/r/20210812053056.1699-1-longpeng2@huawei.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- 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 2700a63ab095..3a056f8affd1 100644 --- a/net/vmw_vsock/virtio_transport.c +++ b/net/vmw_vsock/virtio_transport.c @@ -356,11 +356,14 @@ 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->sk_error_report(sk); - release_sock(sk); } static void virtio_vsock_update_guest_cid(struct virtio_vsock *vsock) -- 2.30.2