Commit 7f988eab authored Jul 30, 2007 by Herbert Xu Committed by David S. Miller Jul 31, 2007

[NET]: Take dev_base_lock when moving device name hash list entry

When we added name-based hashing the dev_base_lock was designated as the
lock to take when changing the name hash list. Unfortunately, because
it was a preexisting lock that just happened to be taken in the right
spots we neglected to take it in dev_change_name.

The race can affect calles of __dev_get_by_name that do so without taking
the RTNL. They may end up walking down the wrong hash chain and end up
missing the device that they're looking for.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent 7ce1b0ed

net/core/dev.c

+4 −0

Original line number	Diff line number	Diff line
		@@ -839,8 +839,12 @@ int dev_change_name(struct net_device dev, char newname)
		strlcpy(dev->name, newname, IFNAMSIZ);

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

		write_lock_bh(&dev_base_lock);
		hlist_del(&dev->name_hlist);
		hlist_add_head(&dev->name_hlist, dev_name_hash(dev->name));
		write_unlock_bh(&dev_base_lock);

		raw_notifier_call_chain(&netdev_chain, NETDEV_CHANGENAME, dev);

		return err;