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=-8.4 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,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 53088C2D0DB for ; Fri, 24 Jan 2020 13:46:34 +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 1D15E2072C for ; Fri, 24 Jan 2020 13:46:34 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="X9NmUYf8" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1D15E2072C 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]:42540 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iuzI9-0005ib-BV for qemu-devel@archiver.kernel.org; Fri, 24 Jan 2020 08:46:33 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:37041) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iuzGt-0004dZ-8U for qemu-devel@nongnu.org; Fri, 24 Jan 2020 08:45:16 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1iuzGr-0002VU-R0 for qemu-devel@nongnu.org; Fri, 24 Jan 2020 08:45:15 -0500 Received: from us-smtp-2.mimecast.com ([207.211.31.81]:39597 helo=us-smtp-delivery-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1iuzGr-0002U5-Na for qemu-devel@nongnu.org; Fri, 24 Jan 2020 08:45:13 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1579873513; 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=LRNoohjl+q/gi015jicWp1LxYjqP0NPbbX/wUs1JD6U=; b=X9NmUYf8e2WfILP6IYVQN6Dkm+c9R1Ctr34/wWhd2EOEdNgtJgdSHvQHsgIF2jbrLOBEX+ ZaaZy4RRU4G3yNrVAkFMUZBuXScm2wSSH8yaHeIM9DL3SkK+Cdj98hoK4qUrGZgeyoHkOp 6rtlOkc057l71XGWJnq7cJvX5NpWdtw= 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-175-jCQBPnHoMVeN8FOezPS5jQ-1; Fri, 24 Jan 2020 08:45:11 -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 264431005514; Fri, 24 Jan 2020 13:45:10 +0000 (UTC) Received: from dhcp-200-226.str.redhat.com (dhcp-200-226.str.redhat.com [10.33.200.226]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 957C185F13; Fri, 24 Jan 2020 13:45:06 +0000 (UTC) Date: Fri, 24 Jan 2020 14:45:04 +0100 From: Kevin Wolf To: John Snow Subject: Re: [PATCH] iscsi: Don't access non-existent scsi_lba_status_descriptor Message-ID: <20200124134504.GE4732@dhcp-200-226.str.redhat.com> References: <20200123170544.30117-1-kwolf@redhat.com> MIME-Version: 1.0 In-Reply-To: User-Agent: Mutt/1.12.1 (2019-06-15) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-MC-Unique: jCQBPnHoMVeN8FOezPS5jQ-1 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: quoted-printable Content-Disposition: inline X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 207.211.31.81 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: qemu-block@nongnu.org, pl@kamp.de, qemu-devel@nongnu.org, mreitz@redhat.com, ronniesahlberg@gmail.com, felipe@nutanix.com, pbonzini@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Am 23.01.2020 um 21:37 hat John Snow geschrieben: > On 1/23/20 12:05 PM, Kevin Wolf wrote: > > In iscsi_co_block_status(), we may have received num_descriptors =3D=3D= 0 > > from the iscsi server. Therefore, we can't unconditionally access > > lbas->descriptors[0]. Add the missing check. > >=20 > > Signed-off-by: Kevin Wolf > > --- > > block/iscsi.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > >=20 > > diff --git a/block/iscsi.c b/block/iscsi.c > > index cbd57294ab..c8feaa2f0e 100644 > > --- a/block/iscsi.c > > +++ b/block/iscsi.c > > @@ -753,7 +753,7 @@ retry: > > } > > =20 > > lbas =3D scsi_datain_unmarshall(iTask.task); > > - if (lbas =3D=3D NULL) { > > + if (lbas =3D=3D NULL || lbas->num_descriptors =3D=3D 0) { > > ret =3D -EIO; > > goto out_unlock; > > } > >=20 >=20 > Naive question: Does the specification allow for such a response? Is > this inherently an error? Even if iscsi allowed it, it would be a useless response, because it means that you didn't get the block status of any block. bdrv_co_block_status() may only return *pnum =3D=3D 0 at EOF, so I don't think we have any other option than returning an error. (We could retry, but if a target returns a useless response once, why should we trust it do behave better the second time?) > Anyway, this is better than accessing junk memory, so: >=20 > Reviewed-by: John Snow Thanks! Kevin