netdev - Re: [PATCH net RESEND] bridge: flush br's address entry in fdb when remove the bridge dev

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Message-ID: <528C0AE3.5070105@huawei.com>
Date:	Wed, 20 Nov 2013 09:05:39 +0800
From:	Ding Tianhong <dingtianhong@...wei.com>
To:	Vlad Yasevich <vyasevich@...il.com>,
	Stephen Hemminger <stephen@...workplumber.org>,
	"David S. Miller" <davem@...emloft.net>,
	<bridge@...ts.linux-foundation.org>,
	Netdev <netdev@...r.kernel.org>
Subject: Re: [PATCH net RESEND] bridge: flush br's address entry in fdb when
 remove the bridge dev

On 2013/11/19 23:52, Vlad Yasevich wrote:
> On 11/18/2013 09:57 PM, Ding Tianhong wrote:
>> When the following commands are executed:
>>
>> brctl addbr br0
>> ifconfig br0 hw ether <addr>
>> rmmod bridge
>>
>> The calltrace will occur:
>>
>> [  563.312114] device eth1 left promiscuous mode
>> [  563.312188] br0: port 1(eth1) entered disabled state
>> [  563.468190] kmem_cache_destroy bridge_fdb_cache: Slab cache still has objects
>> [  563.468197] CPU: 6 PID: 6982 Comm: rmmod Tainted: G           O 3.12.0-0.7-default+ #9
>> [  563.468199] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2007
>> [  563.468200]  0000000000000880 ffff88010f111e98 ffffffff814d1c92 ffff88010f111eb8
>> [  563.468204]  ffffffff81148efd ffff88010f111eb8 0000000000000000 ffff88010f111ec8
>> [  563.468206]  ffffffffa062a270 ffff88010f111ed8 ffffffffa063ac76 ffff88010f111f78
>> [  563.468209] Call Trace:
>> [  563.468218]  [<ffffffff814d1c92>] dump_stack+0x6a/0x78
>> [  563.468234]  [<ffffffff81148efd>] kmem_cache_destroy+0xfd/0x100
>> [  563.468242]  [<ffffffffa062a270>] br_fdb_fini+0x10/0x20 [bridge]
>> [  563.468247]  [<ffffffffa063ac76>] br_deinit+0x4e/0x50 [bridge]
>> [  563.468254]  [<ffffffff810c7dc9>] SyS_delete_module+0x199/0x2b0
>> [  563.468259]  [<ffffffff814e0922>] system_call_fastpath+0x16/0x1b
>> [  570.377958] Bridge firewalling registered
>>
>> ------------------------------------------------
>>
>> The reason is that when the bridge dev's address is changed, the
>> br_fdb_change_mac_address() will add new address in fdb, but when
>> the bridge was removed, the address entry in the fdb did not free,
>> the bridge_fdb_cache still has objects when destroy the cache, Fix
>> this by flushing the bridge address entry when removing the bridge.
>>
>> Signed-off-by: Ding Tianhong <dingtianhong@...wei.com>
>> ---
>>  net/bridge/br_if.c | 4 ++++
>>  1 file changed, 4 insertions(+)
>>
>> diff --git a/net/bridge/br_if.c b/net/bridge/br_if.c
>> index 6e6194f..98084d8 100644
>> --- a/net/bridge/br_if.c
>> +++ b/net/bridge/br_if.c
>> @@ -172,6 +172,10 @@ void br_dev_delete(struct net_device *dev, struct list_head *head)
>>  		del_nbp(p);
>>  	}
>>  
>> +	spin_lock_bh(&br->hash_lock);
>> +	fdb_delete_by_addr(br, br->dev->dev_addr, 0);
>> +	spin_unlock_bh(&br->hash_lock);
>> +
>>  	br_vlan_flush(br);
>>  	del_timer_sync(&br->gc_timer);
>>  
>>
> 
> I think you need to use fdb_delete_by_port(br, NULL, 1);  here.
> 
> The reason is that if the bridge had vlan filtering configured, when the
> bridge mac address was changed, an fdb would have been created for
> for ever vlan configured on the bridge.  You delete only vlan0, so you
> would still have a leak.
> 
> -vlad

agree, I miss the vid problem, I will fix it.

Regards
Ding

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