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authorJiri Pirko <jiri@resnulli.us>2015-01-14 18:15:30 +0100
committerDavid S. Miller <davem@davemloft.net>2015-01-14 16:53:57 -0500
commitb0d11b42785b70e19bc6a3122eead3f7969a7589 (patch)
tree06ca980eca49523be349e19fdbd50c2e090d7f6f /drivers/net/team
parent1ba398041f5b5a15456ea20a9ba3ff80b6a4e7d1 (diff)
team: avoid possible underflow of count_pending value for notify_peers and mcast_rejoin
This patch is fixing a race condition that may cause setting count_pending to -1, which results in unwanted big bulk of arp messages (in case of "notify peers"). Consider following scenario: count_pending == 2 CPU0 CPU1 team_notify_peers_work atomic_dec_and_test (dec count_pending to 1) schedule_delayed_work team_notify_peers atomic_add (adding 1 to count_pending) team_notify_peers_work atomic_dec_and_test (dec count_pending to 1) schedule_delayed_work team_notify_peers_work atomic_dec_and_test (dec count_pending to 0) schedule_delayed_work team_notify_peers_work atomic_dec_and_test (dec count_pending to -1) Fix this race by using atomic_dec_if_positive - that will prevent count_pending running under 0. Fixes: fc423ff00df3a1955441 ("team: add peer notification") Fixes: 492b200efdd20b8fcfd ("team: add support for sending multicast rejoins") Signed-off-by: Jiri Pirko <jiri@resnulli.us> Signed-off-by: Jiri Benc <jbenc@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/net/team')
-rw-r--r--drivers/net/team/team.c16
1 files changed, 14 insertions, 2 deletions
diff --git a/drivers/net/team/team.c b/drivers/net/team/team.c
index 93e224217e24..f7ff493f1e73 100644
--- a/drivers/net/team/team.c
+++ b/drivers/net/team/team.c
@@ -629,6 +629,7 @@ static int team_change_mode(struct team *team, const char *kind)
static void team_notify_peers_work(struct work_struct *work)
{
struct team *team;
+ int val;
team = container_of(work, struct team, notify_peers.dw.work);
@@ -636,9 +637,14 @@ static void team_notify_peers_work(struct work_struct *work)
schedule_delayed_work(&team->notify_peers.dw, 0);
return;
}
+ val = atomic_dec_if_positive(&team->notify_peers.count_pending);
+ if (val < 0) {
+ rtnl_unlock();
+ return;
+ }
call_netdevice_notifiers(NETDEV_NOTIFY_PEERS, team->dev);
rtnl_unlock();
- if (!atomic_dec_and_test(&team->notify_peers.count_pending))
+ if (val)
schedule_delayed_work(&team->notify_peers.dw,
msecs_to_jiffies(team->notify_peers.interval));
}
@@ -669,6 +675,7 @@ static void team_notify_peers_fini(struct team *team)
static void team_mcast_rejoin_work(struct work_struct *work)
{
struct team *team;
+ int val;
team = container_of(work, struct team, mcast_rejoin.dw.work);
@@ -676,9 +683,14 @@ static void team_mcast_rejoin_work(struct work_struct *work)
schedule_delayed_work(&team->mcast_rejoin.dw, 0);
return;
}
+ val = atomic_dec_if_positive(&team->mcast_rejoin.count_pending);
+ if (val < 0) {
+ rtnl_unlock();
+ return;
+ }
call_netdevice_notifiers(NETDEV_RESEND_IGMP, team->dev);
rtnl_unlock();
- if (!atomic_dec_and_test(&team->mcast_rejoin.count_pending))
+ if (val)
schedule_delayed_work(&team->mcast_rejoin.dw,
msecs_to_jiffies(team->mcast_rejoin.interval));
}