[PATCH] bonding: fix deadlock on high loads in bond_alb_monitor()

In bond_alb_monitor the bond->curr_slave_lock write lock is taken
and then dev_set_promiscuity maybe called which can take some time,
depending on the network HW. If a network IRQ for this card come in
the softirq handler maybe try to deliver more packets which end up in
a request to the read lock of bond->curr_slave_lock -> deadlock.
This issue was found by a test lab during network stress tests, this patch
disable the softirq handler for this case and solved the issue.

Signed-off-by: Karsten Keil <kkeil@suse.de>
Acked-by: Jay Vosburgh <fubar@us.ibm.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

diff --git a/drivers/net/bonding/bond_alb.c b/drivers/net/bonding/bond_alb.c
index e83bc825f6afc4d5346cbb3d70f999e4b5d44e75..32923162179ef8b45948149972343744144694ec 100644 (file)
--- a/drivers/net/bonding/bond_alb.c
+++ b/drivers/net/bonding/bond_alb.c
@@ -1433,7 +1433,7 @@ void bond_alb_monitor(struct bonding *bond)
                 * write lock to protect from other code that also
                 * sets the promiscuity.
                 */
-               write_lock(&bond->curr_slave_lock);
+               write_lock_bh(&bond->curr_slave_lock);
 
                if (bond_info->primary_is_promisc &&
                    (++bond_info->rlb_promisc_timeout_counter >= RLB_PROMISC_TIMEOUT)) {
@@ -1448,7 +1448,7 @@ void bond_alb_monitor(struct bonding *bond)
                        bond_info->primary_is_promisc = 0;
                }
 
-               write_unlock(&bond->curr_slave_lock);
+               write_unlock_bh(&bond->curr_slave_lock);
 
                if (bond_info->rlb_rebalance) {
                        bond_info->rlb_rebalance = 0;