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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 1F365CD5BA0 for ; Thu, 13 Nov 2025 09:07:43 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1vJTIg-0004g9-Pk; Thu, 13 Nov 2025 04:07:30 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1vJTIf-0004fL-3h for qemu-devel@nongnu.org; Thu, 13 Nov 2025 04:07:29 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1vJTId-0006Gl-4b for qemu-devel@nongnu.org; Thu, 13 Nov 2025 04:07:28 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1763024843; h=from:from:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:in-reply-to:in-reply-to: references:references; bh=AdHSlZNLdNEXCHS+wkPv/CQN5ik2ky+PiU98l298csY=; b=UA3dE9xvqZhUSA2EDG4UFShhXn49Pn74IvSDeDfmu3C01ohdR4jnJlvJYvq/ZUt6Z6CA6/ ulPEgMe3LBWfVkFYCdEWnmHBEDxbn0yLY/wIgP8Olk4w5X1gzETzzVQa9A5/a0gVDrFakR U9hWiH84pxrJK2FPuQNqykhb/+I93Cg= Received: from mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-330-QZu7uGZdObWy4PfOc1cdFw-1; Thu, 13 Nov 2025 04:07:21 -0500 X-MC-Unique: QZu7uGZdObWy4PfOc1cdFw-1 X-Mimecast-MFC-AGG-ID: QZu7uGZdObWy4PfOc1cdFw_1763024841 Received: from mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.93]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id DC30D180047F; Thu, 13 Nov 2025 09:07:20 +0000 (UTC) Received: from redhat.com (unknown [10.42.28.56]) by mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id B14F218004A3; Thu, 13 Nov 2025 09:07:18 +0000 (UTC) Date: Thu, 13 Nov 2025 09:07:14 +0000 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Eric Blake Cc: qemu-devel@nongnu.org, qemu-block@nongnu.org, kwolf@redhat.com Subject: Re: [PATCH v3 for-10.2 00/13] Fix deadlock with bdrv_open of self-served NBD Message-ID: References: <20251113011625.878876-15-eblake@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20251113011625.878876-15-eblake@redhat.com> User-Agent: Mutt/2.2.14 (2025-02-20) X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.93 Received-SPF: pass client-ip=170.10.133.124; envelope-from=berrange@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, RCVD_IN_VALIDITY_CERTIFIED_BLOCKED=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, SPF_HELO_PASS=-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: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Seems you sent a v3 twice today. I reviewed the earlier v3 and assume this v3 is an identical accident dupe. If this is actually a v3 let me know and i'll review further... On Wed, Nov 12, 2025 at 07:11:25PM -0600, Eric Blake wrote: > v2 was here: > https://lists.nongnu.org/archive/html/qemu-devel/2025-11/msg01243.html > > Since then: > - drop patch 7/12; refcounting for GSource case is now unchanged > - add a couple of patches: fix a chardev leaky abstraction, and add a > mutex lock for cross-thread safety > - improve commit messages to document why NBD is safe now, even without > adding notify callbacks to AioContext > > Now that the new behavior is opt-in rather than a change of defaults, > and only NBD opts in, it should still be safe to include in 10.2. > But the technical debt here means that we really should consider > improving the AioContext API for 11.0 to allow for a notify function > similar to what GSource provides. > > Key: > [----] : patches are identical > [####] : number of functional differences between upstream/downstream patch > [down] : patch is downstream-only > The flags [FC] indicate (F)unctional and (C)ontextual differences, respectively > > 001/13:[----] [--] 'iotests: Drop execute permissions on vvfat.out' > 002/13:[----] [--] 'qio: Add trace points to net_listener' > 003/13:[----] [--] 'qio: Unwatch before notify in QIONetListener' > 004/13:[----] [--] 'qio: Remember context of qio_net_listener_set_client_func_full' > 005/13:[down] 'qio: Protect NetListener callback with mutex' > 006/13:[----] [-C] 'qio: Minor optimization when callback function is unchanged' > 007/13:[0042] [FC] 'qio: Factor out helpers qio_net_listener_[un]watch' > 008/13:[down] 'chardev: Reuse channel's cached local address' > 009/13:[0053] [FC] 'qio: Provide accessor around QIONetListener->sioc' > 010/13:[0013] [FC] 'qio: Prepare NetListener to use AioContext' > 011/13:[0041] [FC] 'qio: Add QIONetListener API for using AioContext' > 012/13:[----] [--] 'nbd: Avoid deadlock in client connecting to same-process server' > 013/13:[----] [--] 'iotests: Add coverage of recent NBD qio deadlock fix' > > Eric Blake (13): > iotests: Drop execute permissions on vvfat.out > qio: Add trace points to net_listener > qio: Unwatch before notify in QIONetListener > qio: Remember context of qio_net_listener_set_client_func_full > qio: Protect NetListener callback with mutex > qio: Minor optimization when callback function is unchanged > qio: Factor out helpers qio_net_listener_[un]watch > chardev: Reuse channel's cached local address > qio: Provide accessor around QIONetListener->sioc > qio: Prepare NetListener to use AioContext > qio: Add QIONetListener API for using AioContext > nbd: Avoid deadlock in client connecting to same-process server > iotests: Add coverage of recent NBD qio deadlock fix > > include/io/channel-socket.h | 2 +- > include/io/net-listener.h | 71 ++++- > blockdev-nbd.c | 4 +- > chardev/char-socket.c | 2 +- > io/net-listener.c | 300 +++++++++++++----- > migration/socket.c | 4 +- > ui/vnc.c | 34 +- > io/trace-events | 5 + > tests/qemu-iotests/tests/nbd-in-qcow2-chain | 94 ++++++ > .../qemu-iotests/tests/nbd-in-qcow2-chain.out | 75 +++++ > tests/qemu-iotests/tests/vvfat.out | 0 > 11 files changed, 498 insertions(+), 93 deletions(-) > create mode 100755 tests/qemu-iotests/tests/nbd-in-qcow2-chain > create mode 100644 tests/qemu-iotests/tests/nbd-in-qcow2-chain.out > mode change 100755 => 100644 tests/qemu-iotests/tests/vvfat.out > > -- > 2.51.1 > With regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|