| From foo@baz Sun Jan 10 01:16:11 PM CET 2021 |
| From: Yunjian Wang <wangyunjian@huawei.com> |
| Date: Tue, 29 Dec 2020 10:01:48 +0800 |
| Subject: vhost_net: fix ubuf refcount incorrectly when sendmsg fails |
| |
| From: Yunjian Wang <wangyunjian@huawei.com> |
| |
| [ Upstream commit 01e31bea7e622f1890c274f4aaaaf8bccd296aa5 ] |
| |
| 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: bab632d69ee4 ("vhost: vhost TX zero-copy support") |
| Signed-off-by: Yunjian Wang <wangyunjian@huawei.com> |
| Acked-by: Willem de Bruijn <willemb@google.com> |
| Acked-by: Michael S. Tsirkin <mst@redhat.com> |
| Acked-by: Jason Wang <jasowang@redhat.com> |
| Link: https://lore.kernel.org/r/1609207308-20544-1-git-send-email-wangyunjian@huawei.com |
| Signed-off-by: Jakub Kicinski <kuba@kernel.org> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| --- |
| drivers/vhost/net.c | 6 +++--- |
| 1 file changed, 3 insertions(+), 3 deletions(-) |
| |
| --- a/drivers/vhost/net.c |
| +++ b/drivers/vhost/net.c |
| @@ -313,6 +313,7 @@ static void handle_tx(struct vhost_net * |
| size_t hdr_size; |
| struct socket *sock; |
| struct vhost_net_ubuf_ref *uninitialized_var(ubufs); |
| + struct ubuf_info *ubuf; |
| bool zcopy, zcopy_used; |
| int sent_pkts = 0; |
| |
| @@ -378,9 +379,7 @@ static void handle_tx(struct vhost_net * |
| |
| /* 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; |
| @@ -399,7 +398,8 @@ static void handle_tx(struct vhost_net * |
| 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; |
| } |