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=-9.9 required=3.0 tests=BAYES_00,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 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 33820C433DF for ; Thu, 8 Oct 2020 20:28:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id ACCAA22227 for ; Thu, 8 Oct 2020 20:28:49 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="Qd5ylcDy" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730393AbgJHU2t (ORCPT ); Thu, 8 Oct 2020 16:28:49 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:60541 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730371AbgJHU2s (ORCPT ); Thu, 8 Oct 2020 16:28:48 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1602188927; 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: in-reply-to:in-reply-to:references:references; bh=caF6a1MKbmv3Qw+xnDNzTfS/1KBH8aRkP9njZDRX0Fs=; b=Qd5ylcDy34T5Glzjuzewf2bUMz+zA6reHTYuBQ8kHWRz+aEJSe/nplZP5/9rDoYgYdFNxy pHDzXqj2DcD5qWETS7WZ935vH2LBh1EhXBvYCxRggyjMkOkC33e8sAma3dYmbWOMaSCZgX tJ1NFKz6wCCWcAO99msgH0wWGVQkaIs= Received: from mail-wr1-f69.google.com (mail-wr1-f69.google.com [209.85.221.69]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-63-K37Gnl6uOrerpTfBwVlYLA-1; Thu, 08 Oct 2020 16:28:45 -0400 X-MC-Unique: K37Gnl6uOrerpTfBwVlYLA-1 Received: by mail-wr1-f69.google.com with SMTP id 33so4315541wrk.12 for ; Thu, 08 Oct 2020 13:28:45 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=caF6a1MKbmv3Qw+xnDNzTfS/1KBH8aRkP9njZDRX0Fs=; b=lr4DWhD5lYq1ubcsK0qGrWAzBA3o7jfBzpy+uUOo807gQRh1E6AdMiKdNRg+KsELZK DGaKqDiFIJDF1v031Ce2uR8Im6I7d5Q0tp8ewsPAzvxW7mM1bMwv/cdmo9z5agWkSDeJ 6e9uHqWwBIYBWLdh7yQHLgKKZ8Q2NI/nUdX/JFYWCJy5lj398yNFnxDTgGT89BHdtxP3 xX5Af9FuPm0pJPt/jUesKMFuCeZNvJlBDMd5bpyUa9kHJUVmKSfIQODrl/IvHaWE3zum 2e5TxayP3qIkle4AQRd15txrCUkcAR+QhDEsMjuajOO33G2ISpqYZ4JCOQzbgIMN74vY RCEA== X-Gm-Message-State: AOAM533Tk94MgQfEYW96AXDpe2icoSXQCoCpsWam/5f9QdKPfyJOobYM iusuF3dzFUJjJOvCO358eD11uT1BiVxVkp3pYBR0eamnfPCTZR375wvTl4PchylqLabmb/MR1jq 6oRatc/9Z8fTRI5Ks X-Received: by 2002:adf:9124:: with SMTP id j33mr11087554wrj.272.1602188923790; Thu, 08 Oct 2020 13:28:43 -0700 (PDT) X-Google-Smtp-Source: ABdhPJzh5A/5Z709VFadlr4JMrgafEqB5aQH7y0RpPTVbx0qmRWUq9A9IgbF5HNIuV7k7UKGbJOfFw== X-Received: by 2002:adf:9124:: with SMTP id j33mr11087542wrj.272.1602188923600; Thu, 08 Oct 2020 13:28:43 -0700 (PDT) Received: from redhat.com (bzq-79-179-71-128.red.bezeqint.net. [79.179.71.128]) by smtp.gmail.com with ESMTPSA id w11sm8605695wrn.27.2020.10.08.13.28.41 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 08 Oct 2020 13:28:42 -0700 (PDT) Date: Thu, 8 Oct 2020 16:28:40 -0400 From: "Michael S. Tsirkin" To: Stefano Garzarella Cc: netdev@vger.kernel.org, virtualization@lists.linux-foundation.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, Rusty Russell , stable@vger.kernel.org, Jason Wang Subject: Re: [PATCH] vringh: fix __vringh_iov() when riov and wiov are different Message-ID: <20201008162813-mutt-send-email-mst@kernel.org> References: <20201008161311.114398-1-sgarzare@redhat.com> <20201008160035-mutt-send-email-mst@kernel.org> <20201008202436.r33jqbbttqynfvhe@steredhat> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201008202436.r33jqbbttqynfvhe@steredhat> Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Thu, Oct 08, 2020 at 10:24:36PM +0200, Stefano Garzarella wrote: > On Thu, Oct 08, 2020 at 04:00:51PM -0400, Michael S. Tsirkin wrote: > > On Thu, Oct 08, 2020 at 06:13:11PM +0200, Stefano Garzarella wrote: > > > If riov and wiov are both defined and they point to different > > > objects, only riov is initialized. If the wiov is not initialized > > > by the caller, the function fails returning -EINVAL and printing > > > "Readable desc 0x... after writable" error message. > > > > > > Let's replace the 'else if' clause with 'if' to initialize both > > > riov and wiov if they are not NULL. > > > > > > As checkpatch pointed out, we also avoid crashing the kernel > > > when riov and wiov are both NULL, replacing BUG() with WARN_ON() > > > and returning -EINVAL. > > > > > > Fixes: f87d0fbb5798 ("vringh: host-side implementation of virtio rings.") > > > Cc: stable@vger.kernel.org > > > Signed-off-by: Stefano Garzarella > > > > Can you add more detail please? when does this trigger? > > I'm developing vdpa_sim_blk and I'm using vringh_getdesc_iotlb() > to get readable and writable buffers. > > With virtio-blk devices a descriptors has both readable and writable > buffers (eg. virtio_blk_outhdr in the readable buffer and status as last byte > of writable buffer). > So, I'm calling vringh_getdesc_iotlb() one time to get both type of buffer > and put them in 2 iovecs: > > ret = vringh_getdesc_iotlb(&vq->vring, &vq->riov, &vq->wiov, > &vq->head, GFP_ATOMIC); > > With this patch applied it works well, without the function fails > returning -EINVAL and printing "Readable desc 0x... after writable". > > Am I using vringh_getdesc_iotlb() in the wrong way? > > Thanks, > Stefano > I think it's ok, this info just needs to be in the commit log ... > > > --- > > > drivers/vhost/vringh.c | 9 +++++---- > > > 1 file changed, 5 insertions(+), 4 deletions(-) > > > > > > diff --git a/drivers/vhost/vringh.c b/drivers/vhost/vringh.c > > > index e059a9a47cdf..8bd8b403f087 100644 > > > --- a/drivers/vhost/vringh.c > > > +++ b/drivers/vhost/vringh.c > > > @@ -284,13 +284,14 @@ __vringh_iov(struct vringh *vrh, u16 i, > > > desc_max = vrh->vring.num; > > > up_next = -1; > > > > > > + /* You must want something! */ > > > + if (WARN_ON(!riov && !wiov)) > > > + return -EINVAL; > > > + > > > if (riov) > > > riov->i = riov->used = 0; > > > - else if (wiov) > > > + if (wiov) > > > wiov->i = wiov->used = 0; > > > - else > > > - /* You must want something! */ > > > - BUG(); > > > > > > for (;;) { > > > void *addr; > > > -- > > > 2.26.2 > >