From: Yunjian Wang Date: Tue, 29 Dec 2020 02:01:48 +0000 (+0800) Subject: vhost_net: fix ubuf refcount incorrectly when sendmsg fails X-Git-Tag: v4.4.251~28 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=8837a932c6c28b4d84166b1401b9692468d524d9;p=thirdparty%2Fkernel%2Fstable.git vhost_net: fix ubuf refcount incorrectly when sendmsg fails [ 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 Acked-by: Willem de Bruijn Acked-by: Michael S. Tsirkin Acked-by: Jason Wang Link: https://lore.kernel.org/r/1609207308-20544-1-git-send-email-wangyunjian@huawei.com Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c index 5efac33c29dcb..3c6ca66cb8194 100644 --- a/drivers/vhost/net.c +++ b/drivers/vhost/net.c @@ -313,6 +313,7 @@ static void handle_tx(struct vhost_net *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 *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 *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; }