From nobody Sun Oct 5 19:23:35 2025 Delivered-To: importer@patchew.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 Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1637590178917204.2830403527696; Mon, 22 Nov 2021 06:09:38 -0800 (PST) Received: from localhost ([::1]:51472 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1mpA0m-0001Qr-PS for importer@patchew.org; Mon, 22 Nov 2021 09:09:36 -0500 Received: from eggs.gnu.org ([209.51.188.92]:45378) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mp9tq-0001Tm-IB for qemu-devel@nongnu.org; Mon, 22 Nov 2021 09:02:26 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:31092) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mp9tj-0006Dq-Qc for qemu-devel@nongnu.org; Mon, 22 Nov 2021 09:02:26 -0500 Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-584-CePcm6EdMvS3f6RByOg1iA-1; Mon, 22 Nov 2021 09:02:15 -0500 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id E1CA919057A0; Mon, 22 Nov 2021 14:02:14 +0000 (UTC) Received: from blue.redhat.com (ovpn-113-22.phx2.redhat.com [10.3.113.22]) by smtp.corp.redhat.com (Postfix) with ESMTP id 8238360862; Mon, 22 Nov 2021 14:02:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1637589739; 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=1s4gIdmWmJJqJEj01NGTgcYt6J2rkpdjZoxa2C8B1BM=; b=SIdj4Sdyx/f9AWExq1ODc8F9qDeXJjnQPher11egEb9cFpgBxZXw+xmPYGnGXZkYGpa7AF lrNeocP3oVlknW4TMk+4rCX/NxrvNOyhv1WD6BOiXX8x4RKDuog/zRqw0eDo+f4nyltojm JfRqpANgIZYtL0NFr/W2aOJBbipbNpY= X-MC-Unique: CePcm6EdMvS3f6RByOg1iA-1 From: Eric Blake To: qemu-devel@nongnu.org Subject: [PULL 1/2] nbd/server: Don't complain on certain client disconnects Date: Mon, 22 Nov 2021 08:02:11 -0600 Message-Id: <20211122140212.1511814-2-eblake@redhat.com> In-Reply-To: <20211122140212.1511814-1-eblake@redhat.com> References: <20211122140212.1511814-1-eblake@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 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-Transfer-Encoding: quoted-printable 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; Received-SPF: pass client-ip=170.10.133.124; envelope-from=eblake@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -34 X-Spam_score: -3.5 X-Spam_bar: --- X-Spam_report: (-3.5 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.709, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=unavailable 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: , Cc: Vladimir Sementsov-Ogievskiy , qemu-stable@nongnu.org, "open list:Network Block Dev..." Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: fail (Header signature does not verify) X-ZM-MESSAGEID: 1637590179706100001 Content-Type: text/plain; charset="utf-8" When a client disconnects abruptly, but did not have any pending requests (for example, when using nbdsh without calling h.shutdown), we used to output the following message: $ qemu-nbd -f raw file $ nbdsh -u 'nbd://localhost:10809' -c 'h.trim(1,0)' qemu-nbd: Disconnect client, due to: Failed to read request: Unexpected end= -of-file before all bytes were read Then in commit f148ae7, we refactored nbd_receive_request() to use nbd_read_eof(); when this returns 0, we regressed into tracing uninitialized memory (if tracing is enabled) and reporting a less-specific: qemu-nbd: Disconnect client, due to: Request handling failed in intermediat= e state Note that with Unix sockets, we have yet another error message, unchanged by the 6.0 regression: $ qemu-nbd -k /tmp/sock -f raw file $ nbdsh -u 'nbd+unix:///?socket=3D/tmp/sock' -c 'h.trim(1,0)' qemu-nbd: Disconnect client, due to: Failed to send reply: Unable to write = to socket: Broken pipe But in all cases, the error message goes away if the client performs a soft shutdown by using NBD_CMD_DISC, rather than a hard shutdown by abrupt disconnect: $ nbdsh -u 'nbd://localhost:10809' -c 'h.trim(1,0)' -c 'h.shutdown()' This patch fixes things to avoid uninitialized memory, and in general avoids warning about a client that does a hard shutdown when not in the middle of a packet. A client that aborts mid-request, or which does not read the full server's reply, can still result in warnings, but those are indeed much more unusual situations. CC: qemu-stable@nongnu.org Fixes: f148ae7d36 ("nbd/server: Quiesce coroutines on context switch", v6.0= .0) Signed-off-by: Eric Blake Reviewed-by: Vladimir Sementsov-Ogievskiy [eblake: defer unrelated typo fixes to later patch] Message-Id: <20211117170230.1128262-2-eblake@redhat.com> Signed-off-by: Eric Blake --- nbd/server.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/nbd/server.c b/nbd/server.c index d9164ee6d0da..74ba48709451 100644 --- a/nbd/server.c +++ b/nbd/server.c @@ -1418,6 +1418,9 @@ static int nbd_receive_request(NBDClient *client, NBD= Request *request, if (ret < 0) { return ret; } + if (ret =3D=3D 0) { + return -EIO; + } /* Request [ 0 .. 3] magic (NBD_REQUEST_MAGIC) --=20 2.33.1