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@huaw... 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 @@ -860,6 +860,7 @@ static void handle_tx_zerocopy(struct vh 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 vh
/* 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 vh 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; }