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=-15.1 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 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 74E1AC433DB for ; Tue, 16 Mar 2021 13:36:37 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id E687D64DD8 for ; Tue, 16 Mar 2021 13:36:36 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E687D64DD8 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:36612 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lM9sB-0005ap-Th for qemu-devel@archiver.kernel.org; Tue, 16 Mar 2021 09:36:35 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:58552) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lM9r5-0004wm-GV for qemu-devel@nongnu.org; Tue, 16 Mar 2021 09:35:27 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:60407) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1lM9r3-0006PM-NH for qemu-devel@nongnu.org; Tue, 16 Mar 2021 09:35:27 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1615901724; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=jlJ8NyvbAUZfwlw/NMErheH42YZsz5w2LFZRcHddi14=; b=SoRidXJCX89fSDIa0kI/TCmomceD9vBd0gYXtz283vIFOyvy9RHxCVbXUhGhliY83gn3+L bseH94F7VPK+EnOxTFoSdtI1Aw2vg0suKLIXZVfvhV6RaoTKw1J/vT1HYFfZFack3seQZu MV3yyETQXZrNyQM5DapA/d5H9Vn17mk= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-273-OlpRAOw0MTipS9fgAKZiVg-1; Tue, 16 Mar 2021 09:35:22 -0400 X-MC-Unique: OlpRAOw0MTipS9fgAKZiVg-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 9EF5718D6A36 for ; Tue, 16 Mar 2021 13:35:21 +0000 (UTC) Received: from [10.3.113.66] (ovpn-113-66.phx2.redhat.com [10.3.113.66]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 012FB5C1A1; Tue, 16 Mar 2021 13:35:14 +0000 (UTC) Subject: Re: [PATCH] sockets: update SOCKET_ADDRESS_TYPE_FD listen(2) backlog To: Stefan Hajnoczi , kraxel@redhat.com, Daniel Berrange References: <20210310173004.420190-1-stefanha@redhat.com> From: Eric Blake Organization: Red Hat, Inc. Message-ID: <2e7bb28d-0b3c-ac69-7984-687d4ee487c7@redhat.com> Date: Tue, 16 Mar 2021 08:35:14 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.8.0 MIME-Version: 1.0 In-Reply-To: X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=eblake@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=windows-1252 Content-Language: en-US Content-Transfer-Encoding: 7bit Received-SPF: pass client-ip=216.205.24.124; envelope-from=eblake@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -29 X-Spam_score: -3.0 X-Spam_bar: --- X-Spam_report: (-3.0 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.25, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, NICE_REPLY_A=-0.001, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Juan Quintela , qemu-devel@nongnu.org, "Richard W . M . Jones" Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 3/16/21 4:10 AM, Stefan Hajnoczi wrote: > On Wed, Mar 10, 2021 at 05:30:04PM +0000, Stefan Hajnoczi wrote: >> socket_get_fd() fails with the error "socket_get_fd: too many >> connections" if the given listen backlog value is not 1. >> >> Not all callers set the backlog to 1. For example, commit >> 582d4210eb2f2ab5baac328fe4b479cd86da1647 ("qemu-nbd: Use SOMAXCONN for >> socket listen() backlog") uses SOMAXCONN. This will always fail with in >> socket_get_fd(). >> >> This patch calls listen(2) on the fd to update the backlog value. The >> socket may already be in the listen state. I have tested that this works >> on Linux 5.10 and macOS Catalina. >> >> As a bonus this allows us to detect when the fd cannot listen. Now we'll >> be able to catch unbound or connected fds in socket_listen(). >> >> Drop the num argument from socket_get_fd() since this function is also >> called by socket_connect() where a listen backlog value does not make >> sense. >> >> Fixes: e5b6353cf25c99c3f08bf51e29933352f7140e8f ("socket: Add backlog parameter to socket_listen") >> Reported-by: Richard W.M. Jones >> Cc: Juan Quintela >> Cc: Eric Blake >> Signed-off-by: Stefan Hajnoczi >> --- >> util/qemu-sockets.c | 29 ++++++++++++++++++++++------- >> 1 file changed, 22 insertions(+), 7 deletions(-) > > Dan and Gerd: Can this go via one of your trees? > As it showed up as a regression in qemu-nbd, I can also consider queuing it in my NBD tree. However, I claim it counts as a bug fix, so it is fine for -rc1 even if it misses soft freeze. I'm fine whichever maintainer takes this, although I've now flagged it to go through an NBD pull request if it doesn't land elsewhere sooner. -- Eric Blake, Principal Software Engineer Red Hat, Inc. +1-919-301-3226 Virtualization: qemu.org | libvirt.org