netdev - Re: [PATCH] net/bonding: Do not transition down slave after speed/duplex check

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <345ca135-6432-a4a0-e681-4822b3575bae@linux.ibm.com>
Date:   Wed, 29 Apr 2020 13:47:45 -0500
From:   Thomas Falcon <tlfalcon@...ux.ibm.com>
To:     Jay Vosburgh <jay.vosburgh@...onical.com>
Cc:     netdev@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org,
        Veaceslav Falico <vfalico@...il.com>,
        Andy Gospodarek <andy@...yhouse.net>
Subject: Re: [PATCH] net/bonding: Do not transition down slave after
 speed/duplex check


On 4/29/20 1:38 PM, Jay Vosburgh wrote:
> Thomas Falcon <tlfalcon@...ux.ibm.com> wrote:
>
>> The following behavior has been observed when testing logical partition
>> migration of LACP-bonded VNIC devices in a PowerVM pseries environment.
>>
>> 1. When performing the migration, the bond master detects that a slave has
>>    lost its link, deactivates the LACP port, and sets the port's
>>    is_enabled flag to false.
>> 2. The slave device then updates it's carrier state to off while it resets
>>    itself. This update triggers a NETDEV_CHANGE notification, which performs
>>    a speed and duplex update. The device does not return a valid speed
>>    and duplex, so the master sets the slave link state to BOND_LINK_FAIL.
>> 3. When the slave VNIC device(s) are active again, some operations, such
>>    as setting the port's is_enabled flag, are not performed when transitioning
>>    the link state back to BOND_LINK_UP from BOND_LINK_FAIL, though the state
>>    prior to the speed check was BOND_LINK_DOWN.
> 	Just to make sure I'm understanding correctly, in regards to
> "the state prior to the speed check was BOND_LINK_DOWN," do you mean
> that during step 1, the slave link is set to BOND_LINK_DOWN, and then in
> step 2 changed from _DOWN to _FAIL?

Yes, that's what I meant, thanks.

>
>> Affected devices are therefore not utilized in the aggregation though they
>> are operational. The simplest way to fix this seems to be to restrict the
>> link state change to devices that are currently up and running.
> 	This sounds similar to an issue from last fall; can you confirm
> that you're running with a kernel that includes:
>
> 1899bb325149 bonding: fix state transition issue in link monitoring
>
> 	-J
> 	

I think so, but I will confirm ASAP.

Tom


>> CC: Jay Vosburgh <j.vosburgh@...il.com>
>> CC: Veaceslav Falico <vfalico@...il.com>
>> CC: Andy Gospodarek <andy@...yhouse.net>
>> Signed-off-by: Thomas Falcon <tlfalcon@...ux.ibm.com>
>> ---
>> drivers/net/bonding/bond_main.c | 3 ++-
>> 1 file changed, 2 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
>> index 2e70e43c5df5..d840da7cd379 100644
>> --- a/drivers/net/bonding/bond_main.c
>> +++ b/drivers/net/bonding/bond_main.c
>> @@ -3175,7 +3175,8 @@ static int bond_slave_netdev_event(unsigned long event,
>> 		 * speeds/duplex are available.
>> 		 */
>> 		if (bond_update_speed_duplex(slave) &&
>> -		    BOND_MODE(bond) == BOND_MODE_8023AD) {
>> +		    BOND_MODE(bond) == BOND_MODE_8023AD &&
>> +		    slave->link == BOND_LINK_UP) {
>> 			if (slave->last_link_up)
>> 				slave->link = BOND_LINK_FAIL;
>> 			else
>> -- 
>> 2.18.2
>>
> ---
> 	-Jay Vosburgh, jay.vosburgh@...onical.com