Patchwork bonding: Fix race condition between bond_enslave() and bond_3ad_update_lacp_rate()

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Submitter Nikolay Aleksandrov
Date Feb. 18, 2013, 12:45 p.m.
Message ID <1361191530-7616-1-git-send-email-nikolay@redhat.com>
Download mbox | patch
Permalink /patch/221294/
State Changes Requested
Delegated to: David Miller
Headers show

Comments

Nikolay Aleksandrov - Feb. 18, 2013, 12:45 p.m.
port->slave can be NULL since it's being initialized in bond_enslave
thus dereferencing a NULL pointer in bond_3ad_update_lacp_rate()
Also fix a minor bug, which could cause a port not to have
AD_STATE_LACP_TIMEOUT since there's no sync between
bond_3ad_update_lacp_rate() and bond_3ad_bind_slave(), by changing
the read_lock to a write_lock_bh in bond_3ad_update_lacp_rate().

Signed-off-by: Nikolay Aleksandrov <nikolay@redhat.com>
---
 drivers/net/bonding/bond_3ad.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

Patch

diff --git a/drivers/net/bonding/bond_3ad.c b/drivers/net/bonding/bond_3ad.c
index a030e63..1720742 100644
--- a/drivers/net/bonding/bond_3ad.c
+++ b/drivers/net/bonding/bond_3ad.c
@@ -2494,11 +2494,13 @@  void bond_3ad_update_lacp_rate(struct bonding *bond)
 	struct port *port = NULL;
 	int lacp_fast;
 
-	read_lock(&bond->lock);
+	write_lock_bh(&bond->lock);
 	lacp_fast = bond->params.lacp_fast;
 
 	bond_for_each_slave(bond, slave, i) {
 		port = &(SLAVE_AD_INFO(slave).port);
+		if (port->slave == NULL)
+			continue;
 		__get_state_machine_lock(port);
 		if (lacp_fast)
 			port->actor_oper_port_state |= AD_STATE_LACP_TIMEOUT;
@@ -2507,5 +2509,5 @@  void bond_3ad_update_lacp_rate(struct bonding *bond)
 		__release_state_machine_lock(port);
 	}
 
-	read_unlock(&bond->lock);
+	write_unlock_bh(&bond->lock);
 }