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[79.179.71.128]) by smtp.gmail.com with ESMTPSA id w11sm8493631wrs.26.2020.10.08.13.00.53 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 08 Oct 2020 13:00:55 -0700 (PDT) Date: Thu, 8 Oct 2020 16:00:51 -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: <20201008160035-mutt-send-email-mst@kernel.org> References: <20201008161311.114398-1-sgarzare@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201008161311.114398-1-sgarzare@redhat.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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? > --- > 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