releases/4.14.112/hv_netvsc-fix-unwanted-wakeup-after-tx_disable.patch

   1 From foo@baz Mon Apr 15 07:47:06 CEST 2019
   2 From: Haiyang Zhang <haiyangz@microsoft.com>
   3 Date: Thu, 28 Mar 2019 19:40:36 +0000
   4 Subject: hv_netvsc: Fix unwanted wakeup after tx_disable
   5
   6 From: Haiyang Zhang <haiyangz@microsoft.com>
   7
   8 [ Upstream commit 1b704c4a1ba95574832e730f23817b651db2aa59 ]
   9
  10 After queue stopped, the wakeup mechanism may wake it up again
  11 when ring buffer usage is lower than a threshold. This may cause
  12 send path panic on NULL pointer when we stopped all tx queues in
  13 netvsc_detach and start removing the netvsc device.
  14
  15 This patch fix it by adding a tx_disable flag to prevent unwanted
  16 queue wakeup.
  17
  18 Fixes: 7b2ee50c0cd5 ("hv_netvsc: common detach logic")
  19 Reported-by: Mohammed Gamal <mgamal@redhat.com>
  20 Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com>
  21 Signed-off-by: David S. Miller <davem@davemloft.net>
  22 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  23 ---
  24  drivers/net/hyperv/hyperv_net.h |    1 +
  25  drivers/net/hyperv/netvsc.c     |    6 ++++--
  26  drivers/net/hyperv/netvsc_drv.c |   32 ++++++++++++++++++++++++++------
  27  3 files changed, 31 insertions(+), 8 deletions(-)
  28
  29 --- a/drivers/net/hyperv/hyperv_net.h
  30 +++ b/drivers/net/hyperv/hyperv_net.h
  31 @@ -779,6 +779,7 @@ struct netvsc_device {
  32
  33         wait_queue_head_t wait_drain;
  34         bool destroy;
  35 +       bool tx_disable; /* if true, do not wake up queue again */
  36
  37         /* Receive buffer allocated by us but manages by NetVSP */
  38         void *recv_buf;
  39 --- a/drivers/net/hyperv/netvsc.c
  40 +++ b/drivers/net/hyperv/netvsc.c
  41 @@ -107,6 +107,7 @@ static struct netvsc_device *alloc_net_d
  42
  43         init_waitqueue_head(&net_device->wait_drain);
  44         net_device->destroy = false;
  45 +       net_device->tx_disable = false;
  46         atomic_set(&net_device->open_cnt, 0);
  47         net_device->max_pkt = RNDIS_MAX_PKT_DEFAULT;
  48         net_device->pkt_align = RNDIS_PKT_ALIGN_DEFAULT;
  49 @@ -712,7 +713,7 @@ static void netvsc_send_tx_complete(stru
  50         } else {
  51                 struct netdev_queue *txq = netdev_get_tx_queue(ndev, q_idx);
  52
  53 -               if (netif_tx_queue_stopped(txq) &&
  54 +               if (netif_tx_queue_stopped(txq) && !net_device->tx_disable &&
  55                     (hv_ringbuf_avail_percent(&channel->outbound) > RING_AVAIL_PERCENT_HIWATER ||
  56                      queue_sends < 1)) {
  57                         netif_tx_wake_queue(txq);
  58 @@ -865,7 +866,8 @@ static inline int netvsc_send_pkt(
  59                         netif_tx_stop_queue(txq);
  60         } else if (ret == -EAGAIN) {
  61                 netif_tx_stop_queue(txq);
  62 -               if (atomic_read(&nvchan->queue_sends) < 1) {
  63 +               if (atomic_read(&nvchan->queue_sends) < 1 &&
  64 +                   !net_device->tx_disable) {
  65                         netif_tx_wake_queue(txq);
  66                         ret = -ENOSPC;
  67                 }
  68 --- a/drivers/net/hyperv/netvsc_drv.c
  69 +++ b/drivers/net/hyperv/netvsc_drv.c
  70 @@ -108,6 +108,15 @@ static void netvsc_set_rx_mode(struct ne
  71         rcu_read_unlock();
  72  }
  73
  74 +static void netvsc_tx_enable(struct netvsc_device *nvscdev,
  75 +                            struct net_device *ndev)
  76 +{
  77 +       nvscdev->tx_disable = false;
  78 +       virt_wmb(); /* ensure queue wake up mechanism is on */
  79 +
  80 +       netif_tx_wake_all_queues(ndev);
  81 +}
  82 +
  83  static int netvsc_open(struct net_device *net)
  84  {
  85         struct net_device_context *ndev_ctx = netdev_priv(net);
  86 @@ -128,7 +137,7 @@ static int netvsc_open(struct net_device
  87         rdev = nvdev->extension;
  88         if (!rdev->link_state) {
  89                 netif_carrier_on(net);
  90 -               netif_tx_wake_all_queues(net);
  91 +               netvsc_tx_enable(nvdev, net);
  92         }
  93
  94         if (vf_netdev) {
  95 @@ -183,6 +192,17 @@ static int netvsc_wait_until_empty(struc
  96         }
  97  }
  98
  99 +static void netvsc_tx_disable(struct netvsc_device *nvscdev,
 100 +                             struct net_device *ndev)
 101 +{
 102 +       if (nvscdev) {
 103 +               nvscdev->tx_disable = true;
 104 +               virt_wmb(); /* ensure txq will not wake up after stop */
 105 +       }
 106 +
 107 +       netif_tx_disable(ndev);
 108 +}
 109 +
 110  static int netvsc_close(struct net_device *net)
 111  {
 112         struct net_device_context *net_device_ctx = netdev_priv(net);
 113 @@ -191,7 +211,7 @@ static int netvsc_close(struct net_devic
 114         struct netvsc_device *nvdev = rtnl_dereference(net_device_ctx->nvdev);
 115         int ret;
 116
 117 -       netif_tx_disable(net);
 118 +       netvsc_tx_disable(nvdev, net);
 119
 120         /* No need to close rndis filter if it is removed already */
 121         if (!nvdev)
 122 @@ -893,7 +913,7 @@ static int netvsc_detach(struct net_devi
 123
 124         /* If device was up (receiving) then shutdown */
 125         if (netif_running(ndev)) {
 126 -               netif_tx_disable(ndev);
 127 +               netvsc_tx_disable(nvdev, ndev);
 128
 129                 ret = rndis_filter_close(nvdev);
 130                 if (ret) {
 131 @@ -1720,7 +1740,7 @@ static void netvsc_link_change(struct wo
 132                 if (rdev->link_state) {
 133                         rdev->link_state = false;
 134                         netif_carrier_on(net);
 135 -                       netif_tx_wake_all_queues(net);
 136 +                       netvsc_tx_enable(net_device, net);
 137                 } else {
 138                         notify = true;
 139                 }
 140 @@ -1730,7 +1750,7 @@ static void netvsc_link_change(struct wo
 141                 if (!rdev->link_state) {
 142                         rdev->link_state = true;
 143                         netif_carrier_off(net);
 144 -                       netif_tx_stop_all_queues(net);
 145 +                       netvsc_tx_disable(net_device, net);
 146                 }
 147                 kfree(event);
 148                 break;
 149 @@ -1739,7 +1759,7 @@ static void netvsc_link_change(struct wo
 150                 if (!rdev->link_state) {
 151                         rdev->link_state = true;
 152                         netif_carrier_off(net);
 153 -                       netif_tx_stop_all_queues(net);
 154 +                       netvsc_tx_disable(net_device, net);
 155                         event->event = RNDIS_STATUS_MEDIA_CONNECT;
 156                         spin_lock_irqsave(&ndev_ctx->lock, flags);
 157                         list_add(&event->list, &ndev_ctx->reconfig_events);