Fix a panic in virtnet_remove. unregister_netdev has already
freed up the netdev (and virtnet_info) due to dev->destructor
being set, while virtnet_info is still required. Remove
virtnet_free altogether, and move the freeing of the per-cpu
statistics from virtnet_free to virtnet_remove.
Tested patch below.
Signed-off-by: Krishna Kumar <krkumar2 at in.ibm.com>
---
(Michael suggested me to re-post with copy to all maintainers)
drivers/net/virtio_net.c | 10 +---------
1 file changed, 1 insertion(+), 9 deletions(-)
diff -ruNp org/drivers/net/virtio_net.c new/drivers/net/virtio_net.c
--- org/drivers/net/virtio_net.c 2011-07-18 09:14:02.000000000 +0530
+++ new/drivers/net/virtio_net.c 2011-07-18 09:16:35.000000000 +0530
@@ -705,14 +705,6 @@ static void virtnet_netpoll(struct net_d
}
#endif
-static void virtnet_free(struct net_device *dev)
-{
- struct virtnet_info *vi = netdev_priv(dev);
-
- free_percpu(vi->stats);
- free_netdev(dev);
-}
-
static int virtnet_open(struct net_device *dev)
{
struct virtnet_info *vi = netdev_priv(dev);
@@ -959,7 +951,6 @@ static int virtnet_probe(struct virtio_d
/* Set up network device as normal. */
dev->netdev_ops = &virtnet_netdev;
dev->features = NETIF_F_HIGHDMA;
- dev->destructor = virtnet_free;
SET_ETHTOOL_OPS(dev, &virtnet_ethtool_ops);
SET_NETDEV_DEV(dev, &vdev->dev);
@@ -1122,6 +1113,7 @@ static void __devexit virtnet_remove(str
while (vi->pages)
__free_pages(get_a_page(vi, GFP_KERNEL), 0);
+ free_percpu(vi->stats);
free_netdev(vi->dev);
}
On Wed, Jul 20, 2011 at 07:26:02PM +0530, Krishna Kumar wrote:> Fix a panic in virtnet_remove. unregister_netdev has already > freed up the netdev (and virtnet_info) due to dev->destructor > being set, while virtnet_info is still required. Remove > virtnet_free altogether, and move the freeing of the per-cpu > statistics from virtnet_free to virtnet_remove. > > Tested patch below. > > Signed-off-by: Krishna Kumar <krkumar2 at in.ibm.com>Also note that the crash was apparently introduced by 3fa2a1df909482cc234524906e4bd30dee3514df in net-next, so this is a net-next only patch. Stephen, was there any special reason to free the memory in the destructor like you did? Acked-by: Michael S. Tsirkin <mst at redhat.com>> --- > (Michael suggested me to re-post with copy to all maintainers) > > drivers/net/virtio_net.c | 10 +--------- > 1 file changed, 1 insertion(+), 9 deletions(-) > > diff -ruNp org/drivers/net/virtio_net.c new/drivers/net/virtio_net.c > --- org/drivers/net/virtio_net.c 2011-07-18 09:14:02.000000000 +0530 > +++ new/drivers/net/virtio_net.c 2011-07-18 09:16:35.000000000 +0530 > @@ -705,14 +705,6 @@ static void virtnet_netpoll(struct net_d > } > #endif > > -static void virtnet_free(struct net_device *dev) > -{ > - struct virtnet_info *vi = netdev_priv(dev); > - > - free_percpu(vi->stats); > - free_netdev(dev); > -} > - > static int virtnet_open(struct net_device *dev) > { > struct virtnet_info *vi = netdev_priv(dev); > @@ -959,7 +951,6 @@ static int virtnet_probe(struct virtio_d > /* Set up network device as normal. */ > dev->netdev_ops = &virtnet_netdev; > dev->features = NETIF_F_HIGHDMA; > - dev->destructor = virtnet_free; > > SET_ETHTOOL_OPS(dev, &virtnet_ethtool_ops); > SET_NETDEV_DEV(dev, &vdev->dev); > @@ -1122,6 +1113,7 @@ static void __devexit virtnet_remove(str > while (vi->pages) > __free_pages(get_a_page(vi, GFP_KERNEL), 0); > > + free_percpu(vi->stats); > free_netdev(vi->dev); > } >
From: "Michael S. Tsirkin" <mst at redhat.com> Date: Wed, 20 Jul 2011 17:31:15 +0300> On Wed, Jul 20, 2011 at 07:26:02PM +0530, Krishna Kumar wrote: >> Fix a panic in virtnet_remove. unregister_netdev has already >> freed up the netdev (and virtnet_info) due to dev->destructor >> being set, while virtnet_info is still required. Remove >> virtnet_free altogether, and move the freeing of the per-cpu >> statistics from virtnet_free to virtnet_remove. >> >> Tested patch below. >> >> Signed-off-by: Krishna Kumar <krkumar2 at in.ibm.com> > > Also note that the crash was apparently introduced by > 3fa2a1df909482cc234524906e4bd30dee3514df in net-next, > so this is a net-next only patch. > > Stephen, was there any special reason to free the memory > in the destructor like you did? > > Acked-by: Michael S. Tsirkin <mst at redhat.com>Applied.