Linux Ethernet Bridging - Dec 2017 - [Bridge] [PATCH net] net: bridge: fix early call to br_stp_change_bridge_id

On 12/18/2017 04:24 AM, Toshiaki Makita wrote:
> On 2017/12/16 20:31, Nikolay Aleksandrov wrote:
[snip]
> ...
>>  	err = br_changelink(dev, tb, data, extack);
>> -	if (err)
>> +	if (err) {
>> +		/* clean possible fdbs from br_stp_change_bridge_id above */
>> +		br_fdb_delete_by_port(br, NULL, 0, 1);
> 
> Don't we need to call br_dev_delete (br_link_ops.dellink) after
> successful register instead of br_fdb_delete?
> Particularly I'm wondering if not calling br_sysfs_delbr() is ok or
not.
> 
Funny, that is actually the only reason we need to call it (br_sysfs_delbr). :-)

Good catch, that is another leak - the bridge sysfs entries are registered when
NETDEV_REGISTER event happens (register_netdevice) but are not properly cleaned
up
on error there. This has also been present since the introduction of changelink
during newlink, commit:
 b6677449dff6 ("bridge: netlink: call br_changelink() during
br_dev_newlink()")

I'll send v2 that does br_dev_delete(dev, NULL) instead of the current
cleanup.
With kobject debug enabled and that I can see "brif" and the rest of
the sysfs
files getting freed properly, while before they weren't.

Thanks,
 Nik

On 12/18/2017 04:22 PM, Nikolay Aleksandrov wrote:
> On 12/18/2017 04:24 AM, Toshiaki Makita wrote:
>> On 2017/12/16 20:31, Nikolay Aleksandrov wrote:
> [snip]
>> ...
>>>  	err = br_changelink(dev, tb, data, extack);
>>> -	if (err)
>>> +	if (err) {
>>> +		/* clean possible fdbs from br_stp_change_bridge_id above */
>>> +		br_fdb_delete_by_port(br, NULL, 0, 1);
>>
>> Don't we need to call br_dev_delete (br_link_ops.dellink) after
>> successful register instead of br_fdb_delete?
>> Particularly I'm wondering if not calling br_sysfs_delbr() is ok or
not.
>>
> 
> Funny, that is actually the only reason we need to call it
(br_sysfs_delbr). :-)
> 
> Good catch, that is another leak - the bridge sysfs entries are registered
when
> NETDEV_REGISTER event happens (register_netdevice) but are not properly
cleaned up
> on error there. This has also been present since the introduction of
changelink
> during newlink, commit:
>  b6677449dff6 ("bridge: netlink: call br_changelink() during
br_dev_newlink()")
err, since the changelink was fixed to be after device registration in commit:
 5b8d5429daa0 ("bridge: netlink: register netdevice before executing
changelink")
> 
> I'll send v2 that does br_dev_delete(dev, NULL) instead of the current
cleanup.
> With kobject debug enabled and that I can see "brif" and the rest
of the sysfs
> files getting freed properly, while before they weren't.
> 
> Thanks,
>  Nik
>