Subject: Re: [PATCH net 2/3] bonding: Fix initialize after use for 3ad machine state spinlock

From: Jay Vosburgh <[email-masked]>
Date: Mon, 18 Feb 2013 13:33:10 -0800

Nikolay Aleksandrov <[email-masked]> wrote:

>The 3ad machine state spinlock can be used before it is inititialized
>while doing bond_enslave() (and the port is being initialized) since
>port->slave is set before the lock is prepared, thus causing soft
>lock-ups and a multitude of other nasty bugs.

	Does this change cause the "uninitialized port" warnings in
bond_3ad_state_machine_handler and bond_3ad_rx_indication to
intermittently print during the enslavement process?  If so (and it
looks to me like it will), I think the warnings should be removed, since
after this change, port->slave being NULL isn't really an error
condition that needs a warning to the log.

>Signed-off-by: Nikolay Aleksandrov <[email-masked]>
>---
> drivers/net/bonding/bond_3ad.c | 9 ++++-----
> 1 file changed, 4 insertions(+), 5 deletions(-)
>
>diff --git a/drivers/net/bonding/bond_3ad.c b/drivers/net/bonding/bond_3ad.c
>index 1720742..96d471e 100644
>--- a/drivers/net/bonding/bond_3ad.c
>+++ b/drivers/net/bonding/bond_3ad.c
>@@ -389,13 +389,13 @@ static u8 __get_duplex(struct port *port)
>
> /**
>  * __initialize_port_locks - initialize a port's STATE machine spinlock
>- * @port: the port we're looking at
>+ * @port: the slave of the port we're looking at
>  *
>  */
>-static inline void __initialize_port_locks(struct port *port)
>+static inline void __initialize_port_locks(struct slave *port)
> {
> 	// make sure it isn't called twice
>-	spin_lock_init(&(SLAVE_AD_INFO(port->slave).state_machine_lock));
>+	spin_lock_init(&(SLAVE_AD_INFO(port).state_machine_lock));

	Change the name of the variable here, too, not just the type.
This is confusing.

	-J

> }
>
> //conversions
>@@ -1910,6 +1910,7 @@ int bond_3ad_bind_slave(struct slave *slave)
>
> 		ad_initialize_port(port, bond->params.lacp_fast);
>
>+		__initialize_port_locks(slave);
> 		port->slave = slave;
> 		port->actor_port_number = SLAVE_AD_INFO(slave).id;
> 		// key is determined according to the link speed, duplex and user key(which is yet not supported)
>@@ -1932,8 +1933,6 @@ int bond_3ad_bind_slave(struct slave *slave)
> 		port->next_port_in_aggregator = NULL;
>
> 		__disable_port(port);
>-		__initialize_port_locks(port);
>-
>
> 		// aggregator initialization
> 		aggregator = &(SLAVE_AD_INFO(slave).aggregator);
>-- 
>1.7.11.7
>

---
	-Jay Vosburgh, IBM Linux Technology Center, [email-masked]