[ 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: Sasha Levin sashal@kernel.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(-)
diff --git a/drivers/net/hyperv/hyperv_net.h b/drivers/net/hyperv/hyperv_net.h index e859ae2e42d5..49f41b64077b 100644 --- a/drivers/net/hyperv/hyperv_net.h +++ b/drivers/net/hyperv/hyperv_net.h @@ -987,6 +987,7 @@ 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; diff --git a/drivers/net/hyperv/netvsc.c b/drivers/net/hyperv/netvsc.c index 813d195bbd57..e0dce373cdd9 100644 --- a/drivers/net/hyperv/netvsc.c +++ b/drivers/net/hyperv/netvsc.c @@ -110,6 +110,7 @@ static struct netvsc_device *alloc_net_device(void)
init_waitqueue_head(&net_device->wait_drain); net_device->destroy = false; + net_device->tx_disable = false;
net_device->max_pkt = RNDIS_MAX_PKT_DEFAULT; net_device->pkt_align = RNDIS_PKT_ALIGN_DEFAULT; @@ -719,7 +720,7 @@ static void netvsc_send_tx_complete(struct net_device *ndev, } 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_get_avail_to_write_percent(&channel->outbound) > RING_AVAIL_PERCENT_HIWATER || queue_sends < 1)) { netif_tx_wake_queue(txq); @@ -874,7 +875,8 @@ static inline int netvsc_send_pkt( } else if (ret == -EAGAIN) { netif_tx_stop_queue(txq); ndev_ctx->eth_stats.stop_queue++; - if (atomic_read(&nvchan->queue_sends) < 1) { + if (atomic_read(&nvchan->queue_sends) < 1 && + !net_device->tx_disable) { netif_tx_wake_queue(txq); ndev_ctx->eth_stats.wake_queue++; ret = -ENOSPC; diff --git a/drivers/net/hyperv/netvsc_drv.c b/drivers/net/hyperv/netvsc_drv.c index cf4897043e83..b20fb0fb595b 100644 --- a/drivers/net/hyperv/netvsc_drv.c +++ b/drivers/net/hyperv/netvsc_drv.c @@ -109,6 +109,15 @@ static void netvsc_set_rx_mode(struct net_device *net) 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); @@ -129,7 +138,7 @@ static int netvsc_open(struct net_device *net) 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) { @@ -184,6 +193,17 @@ static int netvsc_wait_until_empty(struct netvsc_device *nvdev) } }
+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); @@ -192,7 +212,7 @@ static int netvsc_close(struct net_device *net) 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) @@ -920,7 +940,7 @@ static int netvsc_detach(struct net_device *ndev,
/* 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) { @@ -1908,7 +1928,7 @@ static void netvsc_link_change(struct work_struct *w) 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; } @@ -1918,7 +1938,7 @@ static void netvsc_link_change(struct work_struct *w) 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; @@ -1927,7 +1947,7 @@ static void netvsc_link_change(struct work_struct *w) 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);