From: Haiyang Zhang haiyangz@microsoft.com
[ Upstream commit 1b704c4a1ba95574832e730f23817b651db2aa59 ]
After queue stopped, the wakeup mechanism may wake it up again when ring buffer usage is lower than a threshold. This may cause send path panic on NULL pointer when we stopped all tx queues in netvsc_detach and start removing the netvsc device.
This patch fix it by adding a tx_disable flag to prevent unwanted queue wakeup.
Fixes: 7b2ee50c0cd5 ("hv_netvsc: common detach logic") Reported-by: Mohammed Gamal mgamal@redhat.com Signed-off-by: Haiyang Zhang haiyangz@microsoft.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/net/hyperv/hyperv_net.h | 1 + drivers/net/hyperv/netvsc.c | 6 ++++-- drivers/net/hyperv/netvsc_drv.c | 32 ++++++++++++++++++++++++++------ 3 files changed, 31 insertions(+), 8 deletions(-)
--- a/drivers/net/hyperv/hyperv_net.h +++ b/drivers/net/hyperv/hyperv_net.h @@ -779,6 +779,7 @@ struct netvsc_device {
wait_queue_head_t wait_drain; bool destroy; + bool tx_disable; /* if true, do not wake up queue again */
/* Receive buffer allocated by us but manages by NetVSP */ void *recv_buf; --- a/drivers/net/hyperv/netvsc.c +++ b/drivers/net/hyperv/netvsc.c @@ -107,6 +107,7 @@ static struct netvsc_device *alloc_net_d
init_waitqueue_head(&net_device->wait_drain); net_device->destroy = false; + net_device->tx_disable = false; atomic_set(&net_device->open_cnt, 0); net_device->max_pkt = RNDIS_MAX_PKT_DEFAULT; net_device->pkt_align = RNDIS_PKT_ALIGN_DEFAULT; @@ -712,7 +713,7 @@ static void netvsc_send_tx_complete(stru } else { struct netdev_queue *txq = netdev_get_tx_queue(ndev, q_idx);
- if (netif_tx_queue_stopped(txq) && + if (netif_tx_queue_stopped(txq) && !net_device->tx_disable && (hv_ringbuf_avail_percent(&channel->outbound) > RING_AVAIL_PERCENT_HIWATER || queue_sends < 1)) { netif_tx_wake_queue(txq); @@ -865,7 +866,8 @@ static inline int netvsc_send_pkt( netif_tx_stop_queue(txq); } else if (ret == -EAGAIN) { netif_tx_stop_queue(txq); - if (atomic_read(&nvchan->queue_sends) < 1) { + if (atomic_read(&nvchan->queue_sends) < 1 && + !net_device->tx_disable) { netif_tx_wake_queue(txq); ret = -ENOSPC; } --- a/drivers/net/hyperv/netvsc_drv.c +++ b/drivers/net/hyperv/netvsc_drv.c @@ -108,6 +108,15 @@ static void netvsc_set_rx_mode(struct ne rcu_read_unlock(); }
+static void netvsc_tx_enable(struct netvsc_device *nvscdev, + struct net_device *ndev) +{ + nvscdev->tx_disable = false; + virt_wmb(); /* ensure queue wake up mechanism is on */ + + netif_tx_wake_all_queues(ndev); +} + static int netvsc_open(struct net_device *net) { struct net_device_context *ndev_ctx = netdev_priv(net); @@ -128,7 +137,7 @@ static int netvsc_open(struct net_device rdev = nvdev->extension; if (!rdev->link_state) { netif_carrier_on(net); - netif_tx_wake_all_queues(net); + netvsc_tx_enable(nvdev, net); }
if (vf_netdev) { @@ -183,6 +192,17 @@ static int netvsc_wait_until_empty(struc } }
+static void netvsc_tx_disable(struct netvsc_device *nvscdev, + struct net_device *ndev) +{ + if (nvscdev) { + nvscdev->tx_disable = true; + virt_wmb(); /* ensure txq will not wake up after stop */ + } + + netif_tx_disable(ndev); +} + static int netvsc_close(struct net_device *net) { struct net_device_context *net_device_ctx = netdev_priv(net); @@ -191,7 +211,7 @@ static int netvsc_close(struct net_devic struct netvsc_device *nvdev = rtnl_dereference(net_device_ctx->nvdev); int ret;
- netif_tx_disable(net); + netvsc_tx_disable(nvdev, net);
/* No need to close rndis filter if it is removed already */ if (!nvdev) @@ -893,7 +913,7 @@ static int netvsc_detach(struct net_devi
/* If device was up (receiving) then shutdown */ if (netif_running(ndev)) { - netif_tx_disable(ndev); + netvsc_tx_disable(nvdev, ndev);
ret = rndis_filter_close(nvdev); if (ret) { @@ -1720,7 +1740,7 @@ static void netvsc_link_change(struct wo if (rdev->link_state) { rdev->link_state = false; netif_carrier_on(net); - netif_tx_wake_all_queues(net); + netvsc_tx_enable(net_device, net); } else { notify = true; } @@ -1730,7 +1750,7 @@ static void netvsc_link_change(struct wo if (!rdev->link_state) { rdev->link_state = true; netif_carrier_off(net); - netif_tx_stop_all_queues(net); + netvsc_tx_disable(net_device, net); } kfree(event); break; @@ -1739,7 +1759,7 @@ static void netvsc_link_change(struct wo if (!rdev->link_state) { rdev->link_state = true; netif_carrier_off(net); - netif_tx_stop_all_queues(net); + netvsc_tx_disable(net_device, net); event->event = RNDIS_STATUS_MEDIA_CONNECT; spin_lock_irqsave(&ndev_ctx->lock, flags); list_add(&event->list, &ndev_ctx->reconfig_events);