Michael S. Tsirkin
2020-Dec-16 20:56 UTC
[PATCH net v2 1/2] vhost_net: fix ubuf refcount incorrectly when sendmsg fails
On Wed, Dec 16, 2020 at 04:20:20PM +0800, wangyunjian wrote:> From: Yunjian Wang <wangyunjian at huawei.com> > > Currently the vhost_zerocopy_callback() maybe be called to decrease > the refcount when sendmsg fails in tun. The error handling in vhost > handle_tx_zerocopy() will try to decrease the same refcount again. > This is wrong. To fix this issue, we only call vhost_net_ubuf_put() > when vq->heads[nvq->desc].len == VHOST_DMA_IN_PROGRESS. > > Fixes: 0690899b4d45 ("tun: experimental zero copy tx support") > > Signed-off-by: Yunjian Wang <wangyunjian at huawei.com>Acked-by: Michael S. Tsirkin <mst at redhat.com>> --- > drivers/vhost/net.c | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > > diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c > index 531a00d703cd..c8784dfafdd7 100644 > --- a/drivers/vhost/net.c > +++ b/drivers/vhost/net.c > @@ -863,6 +863,7 @@ static void handle_tx_zerocopy(struct vhost_net *net, struct socket *sock) > size_t len, total_len = 0; > int err; > struct vhost_net_ubuf_ref *ubufs; > + struct ubuf_info *ubuf; > bool zcopy_used; > int sent_pkts = 0; > > @@ -895,9 +896,7 @@ static void handle_tx_zerocopy(struct vhost_net *net, struct socket *sock) > > /* use msg_control to pass vhost zerocopy ubuf info to skb */ > if (zcopy_used) { > - struct ubuf_info *ubuf; > ubuf = nvq->ubuf_info + nvq->upend_idx; > - > vq->heads[nvq->upend_idx].id = cpu_to_vhost32(vq, head); > vq->heads[nvq->upend_idx].len = VHOST_DMA_IN_PROGRESS; > ubuf->callback = vhost_zerocopy_callback; > @@ -927,7 +926,8 @@ static void handle_tx_zerocopy(struct vhost_net *net, struct socket *sock) > err = sock->ops->sendmsg(sock, &msg, len); > if (unlikely(err < 0)) { > if (zcopy_used) { > - vhost_net_ubuf_put(ubufs); > + if (vq->heads[ubuf->desc].len == VHOST_DMA_IN_PROGRESS) > + vhost_net_ubuf_put(ubufs); > nvq->upend_idx = ((unsigned)nvq->upend_idx - 1) > % UIO_MAXIOV; > } > -- > 2.23.0