releases/4.19.35/hv_netvsc-fix-unwanted-wakeup-after-tx_disable.patch

   1 From 3fb9bd32e120bbb2f3ec4931570704bf5ef616ef Mon Sep 17 00:00:00 2001
   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 [ Upstream commit 1b704c4a1ba95574832e730f23817b651db2aa59 ]
   7
   8 After queue stopped, the wakeup mechanism may wake it up again
   9 when ring buffer usage is lower than a threshold. This may cause
  10 send path panic on NULL pointer when we stopped all tx queues in
  11 netvsc_detach and start removing the netvsc device.
  12
  13 This patch fix it by adding a tx_disable flag to prevent unwanted
  14 queue wakeup.
  15
  16 Fixes: 7b2ee50c0cd5 ("hv_netvsc: common detach logic")
  17 Reported-by: Mohammed Gamal <mgamal@redhat.com>
  18 Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com>
  19 Signed-off-by: David S. Miller <davem@davemloft.net>
  20 Signed-off-by: Sasha Levin <sashal@kernel.org>
  21 ---
  22  drivers/net/hyperv/hyperv_net.h |  1 +
  23  drivers/net/hyperv/netvsc.c     |  6 ++++--
  24  drivers/net/hyperv/netvsc_drv.c | 32 ++++++++++++++++++++++++++------
  25  3 files changed, 31 insertions(+), 8 deletions(-)
  26
  27 diff --git a/drivers/net/hyperv/hyperv_net.h b/drivers/net/hyperv/hyperv_net.h
  28 index 42d284669b03..31d8d83c25ac 100644
  29 --- a/drivers/net/hyperv/hyperv_net.h
  30 +++ b/drivers/net/hyperv/hyperv_net.h
  31 @@ -970,6 +970,7 @@ 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 diff --git a/drivers/net/hyperv/netvsc.c b/drivers/net/hyperv/netvsc.c
  40 index 1a942feab954..fb12b63439c6 100644
  41 --- a/drivers/net/hyperv/netvsc.c
  42 +++ b/drivers/net/hyperv/netvsc.c
  43 @@ -110,6 +110,7 @@ static struct netvsc_device *alloc_net_device(void)
  44
  45         init_waitqueue_head(&net_device->wait_drain);
  46         net_device->destroy = false;
  47 +       net_device->tx_disable = false;
  48
  49         net_device->max_pkt = RNDIS_MAX_PKT_DEFAULT;
  50         net_device->pkt_align = RNDIS_PKT_ALIGN_DEFAULT;
  51 @@ -716,7 +717,7 @@ static void netvsc_send_tx_complete(struct net_device *ndev,
  52         } else {
  53                 struct netdev_queue *txq = netdev_get_tx_queue(ndev, q_idx);
  54
  55 -               if (netif_tx_queue_stopped(txq) &&
  56 +               if (netif_tx_queue_stopped(txq) && !net_device->tx_disable &&
  57                     (hv_get_avail_to_write_percent(&channel->outbound) >
  58                      RING_AVAIL_PERCENT_HIWATER || queue_sends < 1)) {
  59                         netif_tx_wake_queue(txq);
  60 @@ -871,7 +872,8 @@ static inline int netvsc_send_pkt(
  61         } else if (ret == -EAGAIN) {
  62                 netif_tx_stop_queue(txq);
  63                 ndev_ctx->eth_stats.stop_queue++;
  64 -               if (atomic_read(&nvchan->queue_sends) < 1) {
  65 +               if (atomic_read(&nvchan->queue_sends) < 1 &&
  66 +                   !net_device->tx_disable) {
  67                         netif_tx_wake_queue(txq);
  68                         ndev_ctx->eth_stats.wake_queue++;
  69                         ret = -ENOSPC;
  70 diff --git a/drivers/net/hyperv/netvsc_drv.c b/drivers/net/hyperv/netvsc_drv.c
  71 index c8320405c8f1..9d699bd5f715 100644
  72 --- a/drivers/net/hyperv/netvsc_drv.c
  73 +++ b/drivers/net/hyperv/netvsc_drv.c
  74 @@ -109,6 +109,15 @@ static void netvsc_set_rx_mode(struct net_device *net)
  75         rcu_read_unlock();
  76  }
  77
  78 +static void netvsc_tx_enable(struct netvsc_device *nvscdev,
  79 +                            struct net_device *ndev)
  80 +{
  81 +       nvscdev->tx_disable = false;
  82 +       virt_wmb(); /* ensure queue wake up mechanism is on */
  83 +
  84 +       netif_tx_wake_all_queues(ndev);
  85 +}
  86 +
  87  static int netvsc_open(struct net_device *net)
  88  {
  89         struct net_device_context *ndev_ctx = netdev_priv(net);
  90 @@ -129,7 +138,7 @@ static int netvsc_open(struct net_device *net)
  91         rdev = nvdev->extension;
  92         if (!rdev->link_state) {
  93                 netif_carrier_on(net);
  94 -               netif_tx_wake_all_queues(net);
  95 +               netvsc_tx_enable(nvdev, net);
  96         }
  97
  98         if (vf_netdev) {
  99 @@ -184,6 +193,17 @@ static int netvsc_wait_until_empty(struct netvsc_device *nvdev)
 100         }
 101  }
 102
 103 +static void netvsc_tx_disable(struct netvsc_device *nvscdev,
 104 +                             struct net_device *ndev)
 105 +{
 106 +       if (nvscdev) {
 107 +               nvscdev->tx_disable = true;
 108 +               virt_wmb(); /* ensure txq will not wake up after stop */
 109 +       }
 110 +
 111 +       netif_tx_disable(ndev);
 112 +}
 113 +
 114  static int netvsc_close(struct net_device *net)
 115  {
 116         struct net_device_context *net_device_ctx = netdev_priv(net);
 117 @@ -192,7 +212,7 @@ static int netvsc_close(struct net_device *net)
 118         struct netvsc_device *nvdev = rtnl_dereference(net_device_ctx->nvdev);
 119         int ret;
 120
 121 -       netif_tx_disable(net);
 122 +       netvsc_tx_disable(nvdev, net);
 123
 124         /* No need to close rndis filter if it is removed already */
 125         if (!nvdev)
 126 @@ -918,7 +938,7 @@ static int netvsc_detach(struct net_device *ndev,
 127
 128         /* If device was up (receiving) then shutdown */
 129         if (netif_running(ndev)) {
 130 -               netif_tx_disable(ndev);
 131 +               netvsc_tx_disable(nvdev, ndev);
 132
 133                 ret = rndis_filter_close(nvdev);
 134                 if (ret) {
 135 @@ -1899,7 +1919,7 @@ static void netvsc_link_change(struct work_struct *w)
 136                 if (rdev->link_state) {
 137                         rdev->link_state = false;
 138                         netif_carrier_on(net);
 139 -                       netif_tx_wake_all_queues(net);
 140 +                       netvsc_tx_enable(net_device, net);
 141                 } else {
 142                         notify = true;
 143                 }
 144 @@ -1909,7 +1929,7 @@ static void netvsc_link_change(struct work_struct *w)
 145                 if (!rdev->link_state) {
 146                         rdev->link_state = true;
 147                         netif_carrier_off(net);
 148 -                       netif_tx_stop_all_queues(net);
 149 +                       netvsc_tx_disable(net_device, net);
 150                 }
 151                 kfree(event);
 152                 break;
 153 @@ -1918,7 +1938,7 @@ static void netvsc_link_change(struct work_struct *w)
 154                 if (!rdev->link_state) {
 155                         rdev->link_state = true;
 156                         netif_carrier_off(net);
 157 -                       netif_tx_stop_all_queues(net);
 158 +                       netvsc_tx_disable(net_device, net);
 159                         event->event = RNDIS_STATUS_MEDIA_CONNECT;
 160                         spin_lock_irqsave(&ndev_ctx->lock, flags);
 161                         list_add(&event->list, &ndev_ctx->reconfig_events);
 162 --
 163 2.19.1
 164