Commit 1c07dbb0 authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

net: annotate data-races around dev->name_assign_type 



name_assign_type_show() runs locklessly, we should annotate
accesses to dev->name_assign_type.

Alternative would be to grab devnet_rename_sem semaphore
from name_assign_type_show(), but this would not bring
more accuracy.

Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent b7f9ef72

net/core/dev.c

+3 −3
Original line number Diff line number Diff line
@@ -1228,13 +1228,13 @@ int dev_change_name(struct net_device *dev, const char *newname) 
			    dev->flags & IFF_UP ? " (while UP)" : "");



	old_assign_type = dev->name_assign_type;

	dev->name_assign_type = NET_NAME_RENAMED;

	WRITE_ONCE(dev->name_assign_type, NET_NAME_RENAMED);



rollback:

	ret = device_rename(&dev->dev, dev->name);

	if (ret) {

		memcpy(dev->name, oldname, IFNAMSIZ);

		dev->name_assign_type = old_assign_type;

		WRITE_ONCE(dev->name_assign_type, old_assign_type);

		up_write(&devnet_rename_sem);

		return ret;

	}
@@ -1263,7 +1263,7 @@ int dev_change_name(struct net_device *dev, const char *newname) 
			down_write(&devnet_rename_sem);

			memcpy(dev->name, oldname, IFNAMSIZ);

			memcpy(oldname, newname, IFNAMSIZ);

			dev->name_assign_type = old_assign_type;

			WRITE_ONCE(dev->name_assign_type, old_assign_type);

			old_assign_type = NET_NAME_RENAMED;

			goto rollback;

		} else {

net/core/net-sysfs.c

+2 −2
Original line number Diff line number Diff line
@@ -125,7 +125,7 @@ static DEVICE_ATTR_RO(iflink); 


static ssize_t format_name_assign_type(const struct net_device *dev, char *buf)

{

	return sysfs_emit(buf, fmt_dec, dev->name_assign_type);

	return sysfs_emit(buf, fmt_dec, READ_ONCE(dev->name_assign_type));

}



static ssize_t name_assign_type_show(struct device *dev,
@@ -135,7 +135,7 @@ static ssize_t name_assign_type_show(struct device *dev, 
	struct net_device *ndev = to_net_dev(dev);

	ssize_t ret = -EINVAL;



	if (ndev->name_assign_type != NET_NAME_UNKNOWN)

	if (READ_ONCE(ndev->name_assign_type) != NET_NAME_UNKNOWN)

		ret = netdev_show(dev, attr, buf, format_name_assign_type);



	return ret;