[3.11.y.z extended stable] Patch "virtio-net: fix refill races during restore" has been added to staging queue

[Luis Henriques]

This is a note to let you know that I have just added a patch titled

    virtio-net: fix refill races during restore

to the linux-3.11.y-queue branch of the 3.11.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.11.y-queue

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.11.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From 60ee1dcd6db28870988e990dc8f84f7636d07474 Mon Sep 17 00:00:00 2001
From: Jason Wang <jasowang at redhat.com>
Date: Mon, 30 Dec 2013 11:34:40 +0800
Subject: virtio-net: fix refill races during restore

commit 6cd4ce0099da7702f885b6fa9ebb49e3831d90b4 upstream.

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 at redhat.com>
Cc: Rusty Russell <rusty at rustcorp.com.au>
Cc: Michael S. Tsirkin <mst at redhat.com>
Cc: Eric Dumazet <eric.dumazet at gmail.com>
Signed-off-by: Jason Wang <jasowang at redhat.com>
Signed-off-by: David S. Miller <davem at davemloft.net>
Signed-off-by: Luis Henriques <luis.henriques at 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 68692af..a0c05e0 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -1745,16 +1745,17 @@ 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->curr_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