[PATCH 3.8 163/166] virtio-net: fix refill races during restore

Kamal Mostafa
2014-01-15T21:52:57Z

From: Jason Wang <jasowang@redhat.com>

[ Upstream commit 6cd4ce0099da7702f885b6fa9ebb49e3831d90b4 ]

During restoring, try_fill_recv() was called with neither napi lock nor napi
disabled. This can lead two try_fill_recv() was called in the same time. Fix
this by refilling before trying to enable napi.

Fixes 0741bcb5584f9e2390ae6261573c4de8314999f2
(virtio: net: Add freeze, restore handlers to support S4).

Cc: Amit Shah <amit.shah@redhat.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
[ kamal: backport to 3.8 (context) ]
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
---
drivers/net/virtio_net.c | 11 ++++++-----
1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 8f009899..4380036 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -1723,16 +1723,17 @@ static int virtnet_restore(struct virtio_device *vdev)
if (err)
return err;

- if (netif_running(vi->dev))
+ if (netif_running(vi->dev)) {
+ for (i = 0; i < vi->curr_queue_pairs; i++)
+ if (!try_fill_recv(&vi->rq[i], GFP_KERNEL))
+ schedule_delayed_work(&vi->refill, 0);
+
for (i = 0; i < vi->max_queue_pairs; i++)
virtnet_napi_enable(&vi->rq[i]);
+ }

netif_device_attach(vi->dev);

- for (i = 0; i < vi->max_queue_pairs; i++)
- if (!try_fill_recv(&vi->rq[i], GFP_KERNEL))
- schedule_delayed_work(&vi->refill, 0);
-
mutex_lock(&vi->config_lock);
vi->config_enable = true;
mutex_unlock(&vi->config_lock);
--
1.8.3.2