From nobody Tue Apr 15 14:48:19 2025 Delivered-To: importer@patchew.org Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Authentication-Results: mx.zohomail.com; dkim=fail; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail(p=none dis=none) header.from=redhat.com ARC-Seal: i=1; a=rsa-sha256; t=1582215347; cv=none; d=zohomail.com; s=zohoarc; b=K9XpA3ciCysqFaJnFgLCz4GZlWoib1R+WnSEep/du0QVY1ycBLVyN0MjvBaLk9YPGE6F3PBI/Nh7ZjvJM3S3muMJkxh0V0k3PUh6Up7K+olhAejqt24v03LizKhqXqAg+glGyid8IDn3pWEhxPJXYl/vQ1ziR8k/Ml8mhTzYpJk= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1582215347; h=Content-Type:Content-Transfer-Encoding:Cc:Date:From:In-Reply-To:List-Subscribe:List-Post:List-Id:List-Archive:List-Help:List-Unsubscribe:MIME-Version:Message-ID:References:Sender:Subject:To; bh=ME+RuJBRymVkZGFzUvmwu7dYrlI6PfVNp7T9hjqwwG0=; b=dnwIb/bhrjWG5p2XHWNo/EkDr9m1fA5kuiYUX7VeM4vkbsZ7DuzX6bdPuzXRIf8IpJ5lzeZL0UUoqx4B4yY8AIjEjMbdvpTJLIp+K7l9Rm0/xH+UviFISmNx8CeBJU8VS7u9fLyJXUL9dU1NU4xoApKThZL1CSqWqgL5Zwlng3o= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=fail; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail header.from= (p=none dis=none) header.from= Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1582215347273783.8166363506533; Thu, 20 Feb 2020 08:15:47 -0800 (PST) Received: from localhost ([::1]:45254 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1j4oUL-0006u6-LC for importer@patchew.org; Thu, 20 Feb 2020 11:15:45 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:55085) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1j4oPC-0006n7-NI for qemu-devel@nongnu.org; Thu, 20 Feb 2020 11:10:27 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1j4oPB-0006KR-Jl for qemu-devel@nongnu.org; Thu, 20 Feb 2020 11:10:26 -0500 Received: from us-smtp-delivery-1.mimecast.com ([205.139.110.120]:44183 helo=us-smtp-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1j4oPB-0006KE-FJ for qemu-devel@nongnu.org; Thu, 20 Feb 2020 11:10:25 -0500 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-436-qRftOIdaPm2-HCikafR8MA-1; Thu, 20 Feb 2020 11:10:20 -0500 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 A031019251B7; Thu, 20 Feb 2020 16:10:19 +0000 (UTC) Received: from localhost (unknown [10.36.118.38]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 965F05C1B0; Thu, 20 Feb 2020 16:10:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1582215024; 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=ME+RuJBRymVkZGFzUvmwu7dYrlI6PfVNp7T9hjqwwG0=; b=URtCBIGhygFVpH5FGh62Wqvtx4LfOT7SdkyDO6E/WXHMDKULwHY2b9DlwKohd1Tim5W0VM Cu3N/3EzvgO53fH3wwDJXdKRNes8UuBTpWDgv6pw3ZvG1pUmhZN4pdJ9vXcx/zv7yN46h7 RtGofeQUzBBLJF3NySk1QoB/tm62U98= From: Max Reitz To: qemu-block@nongnu.org Subject: [PULL 10/18] block/nbd: Fix hang in .bdrv_close() Date: Thu, 20 Feb 2020 17:07:02 +0100 Message-Id: <20200220160710.533297-11-mreitz@redhat.com> In-Reply-To: <20200220160710.533297-1-mreitz@redhat.com> References: <20200220160710.533297-1-mreitz@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 X-MC-Unique: qRftOIdaPm2-HCikafR8MA-1 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Transfer-Encoding: quoted-printable X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 205.139.110.120 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: Kevin Wolf , Peter Maydell , qemu-devel@nongnu.org, Max Reitz Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: fail (Header signature does not verify) Content-Type: text/plain; charset="utf-8" When nbd_close() is called from a coroutine, the connection_co never gets to run, and thus nbd_teardown_connection() hangs. This is because aio_co_enter() only puts the connection_co into the main coroutine's wake-up queue, so this main coroutine needs to yield and wait for connection_co to terminate. Suggested-by: Kevin Wolf Signed-off-by: Max Reitz Message-Id: <20200122164532.178040-2-mreitz@redhat.com> Reviewed-by: Eric Blake Reviewed-by: Maxim Levitsky Signed-off-by: Max Reitz --- block/nbd.c | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-) diff --git a/block/nbd.c b/block/nbd.c index d085554f21..6d3b22f844 100644 --- a/block/nbd.c +++ b/block/nbd.c @@ -70,6 +70,7 @@ typedef struct BDRVNBDState { CoMutex send_mutex; CoQueue free_sema; Coroutine *connection_co; + Coroutine *teardown_co; QemuCoSleepState *connection_co_sleep_ns_state; bool drained; bool wait_drained_end; @@ -203,7 +204,15 @@ static void nbd_teardown_connection(BlockDriverState *= bs) qemu_co_sleep_wake(s->connection_co_sleep_ns_state); } } - BDRV_POLL_WHILE(bs, s->connection_co); + if (qemu_in_coroutine()) { + s->teardown_co =3D qemu_coroutine_self(); + /* connection_co resumes us when it terminates */ + qemu_coroutine_yield(); + s->teardown_co =3D NULL; + } else { + BDRV_POLL_WHILE(bs, s->connection_co); + } + assert(!s->connection_co); } =20 static bool nbd_client_connecting(BDRVNBDState *s) @@ -395,6 +404,9 @@ static coroutine_fn void nbd_connection_entry(void *opa= que) s->ioc =3D NULL; } =20 + if (s->teardown_co) { + aio_co_wake(s->teardown_co); + } aio_wait_kick(); } =20 --=20 2.24.1