diff mbox series

[net,v2,1/2] vhost_net: fix ubuf refcount incorrectly when sendmsg fails

Message ID 62db7d3d2af50f379ec28452921b3261af33db0b.1608065644.git.wangyunjian@huawei.com
State Superseded
Headers show
Series [net,v2,1/2] vhost_net: fix ubuf refcount incorrectly when sendmsg fails | expand

Commit Message

wangyunjian Dec. 16, 2020, 8:20 a.m. UTC 
From: Yunjian Wang <wangyunjian@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@huawei.com>
---
 drivers/vhost/net.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

Comments

Willem de Bruijn Dec. 16, 2020, 2:17 p.m. UTC | #1 
On Wed, Dec 16, 2020 at 3:26 AM wangyunjian <wangyunjian@huawei.com> wrote:
>
> From: Yunjian Wang <wangyunjian@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@huawei.com>

Acked-by: Willem de Bruijn <willemb@google.com>

for next time: it's not customary to have an empty line between Fixes
and Signed-off-by
diff mbox series

Patch

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;
 			}