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vhost_net: fix ubuf refcount incorrectly when sendmsg fails 

[ Upstream commit 01e31bea7e ]

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: bab632d69e ("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>
5.4-rM2-2.2.x-imx-squashed
Yunjian Wang 2020-12-29 10:01:48 +08:00 committed by Greg Kroah-Hartman
parent 8f64957fda
commit 5c6eb887e1
1 changed files with 3 additions and 3 deletions
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6
drivers/vhost/net.c
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@ -860,6 +860,7 @@ 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 *uninitialized_var(ubufs);
struct ubuf_info *ubuf;
bool zcopy_used;
int sent_pkts = 0;
@ -892,9 +893,7 @@ 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;
@ -924,7 +923,8 @@ 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;
}