linux/net/bridge
David S. Miller cf124db566 net: Fix inconsistent teardown and release of private netdev state.
Network devices can allocate reasources and private memory using
netdev_ops->ndo_init().  However, the release of these resources
can occur in one of two different places.

Either netdev_ops->ndo_uninit() or netdev->destructor().

The decision of which operation frees the resources depends upon
whether it is necessary for all netdev refs to be released before it
is safe to perform the freeing.

netdev_ops->ndo_uninit() presumably can occur right after the
NETDEV_UNREGISTER notifier completes and the unicast and multicast
address lists are flushed.

netdev->destructor(), on the other hand, does not run until the
netdev references all go away.

Further complicating the situation is that netdev->destructor()
almost universally does also a free_netdev().

This creates a problem for the logic in register_netdevice().
Because all callers of register_netdevice() manage the freeing
of the netdev, and invoke free_netdev(dev) if register_netdevice()
fails.

If netdev_ops->ndo_init() succeeds, but something else fails inside
of register_netdevice(), it does call ndo_ops->ndo_uninit().  But
it is not able to invoke netdev->destructor().

This is because netdev->destructor() will do a free_netdev() and
then the caller of register_netdevice() will do the same.

However, this means that the resources that would normally be released
by netdev->destructor() will not be.

Over the years drivers have added local hacks to deal with this, by
invoking their destructor parts by hand when register_netdevice()
fails.

Many drivers do not try to deal with this, and instead we have leaks.

Let's close this hole by formalizing the distinction between what
private things need to be freed up by netdev->destructor() and whether
the driver needs unregister_netdevice() to perform the free_netdev().

netdev->priv_destructor() performs all actions to free up the private
resources that used to be freed by netdev->destructor(), except for
free_netdev().

netdev->needs_free_netdev is a boolean that indicates whether
free_netdev() should be done at the end of unregister_netdevice().

Now, register_netdevice() can sanely release all resources after
ndo_ops->ndo_init() succeeds, by invoking both ndo_ops->ndo_uninit()
and netdev->priv_destructor().

And at the end of unregister_netdevice(), we invoke
netdev->priv_destructor() and optionally call free_netdev().

Signed-off-by: David S. Miller <davem@davemloft.net>
2017-06-07 15:53:24 -04:00
..
netfilter ebtables: arpreply: Add the standard target sanity check 2017-05-16 10:24:27 +02:00
br_device.c net: Fix inconsistent teardown and release of private netdev state. 2017-06-07 15:53:24 -04:00
br_fdb.c net: bridge: Fix improper taking over HW learned FDB 2017-04-30 22:46:32 -04:00
br_forward.c bridge: add per-port broadcast flood flag 2017-04-27 16:34:29 -04:00
br_if.c bridge: add per-port broadcast flood flag 2017-04-27 16:34:29 -04:00
br_input.c bridge: drop netfilter fake rtable unconditionally 2017-03-13 13:01:10 -07:00
br_ioctl.c bridge: move to workqueue gc 2017-02-06 22:53:13 -05:00
br_mdb.c net: rtnetlink: plumb extended ack to doit function 2017-04-17 15:35:38 -04:00
br_multicast.c bridge: implement missing ndo_uninit() 2017-04-11 22:22:44 -04:00
br_netfilter_hooks.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-03-23 16:41:27 -07:00
br_netfilter_ipv6.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
br_netlink_tunnel.c netlink: pass extended ACK struct to parsing functions 2017-04-13 13:58:22 -04:00
br_netlink.c net: bridge: fix a null pointer dereference in br_afspec 2017-06-06 16:05:31 -04:00
br_nf_core.c net: Remove protocol from struct dst_ops 2015-03-09 16:06:10 -04:00
br_private_stp.h net: bridge: add helper to set topology change 2016-12-10 21:27:23 -05:00
br_private_tunnel.h bridge: vlan dst_metadata hooks in ingress and egress paths 2017-02-03 15:21:22 -05:00
br_private.h bridge: implement missing ndo_uninit() 2017-04-11 22:22:44 -04:00
br_stp_bpdu.c netfilter: Pass net into okfn 2015-09-17 17:18:37 -07:00
br_stp_if.c net: bridge: start hello timer only if device is up 2017-06-01 12:28:31 -04:00
br_stp_timer.c bridge: start hello_timer when enabling KERNEL_STP in br_stp_start 2017-05-21 13:33:28 -04:00
br_stp.c bridge: move to workqueue gc 2017-02-06 22:53:13 -05:00
br_switchdev.c bridge: switchdev: Add forward mark support for stacked devices 2016-08-26 13:13:36 -07:00
br_sysfs_br.c sched/headers: Prepare to move signal wakeup & sigpending methods from <linux/sched.h> into <linux/sched/signal.h> 2017-03-02 08:42:32 +01:00
br_sysfs_if.c bridge: add per-port broadcast flood flag 2017-04-27 16:34:29 -04:00
br_vlan_tunnel.c bridge: vlan_tunnel: explicitly reset metadata attrs to NULL on failure 2017-02-17 13:33:41 -05:00
br_vlan.c bridge: Fix error path in nbp_vlan_init 2017-03-01 14:55:28 -08:00
br.c netfilter: bridge: clarify bridge/netfilter message 2016-10-02 22:44:03 -04:00
Kconfig bridge: Add vlan filtering infrastructure 2013-02-13 19:41:46 -05:00
Makefile bridge: per vlan dst_metadata netlink support 2017-02-03 15:21:22 -05:00