linux/drivers/net/team
Jiri Pirko b0d11b4278 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: fc423ff00d ("team: add peer notification")
Fixes: 492b200efd  ("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>
2015-01-14 16:53:57 -05:00
..
Kconfig team: introduce random mode 2013-03-06 14:55:20 -05:00
Makefile team: introduce random mode 2013-03-06 14:55:20 -05:00
team.c team: avoid possible underflow of count_pending value for notify_peers and mcast_rejoin 2015-01-14 16:53:57 -05:00
team_mode_activebackup.c team: ab: set active port option as changed when port is leaving 2013-02-04 14:55:45 -05:00
team_mode_broadcast.c team: introduce two default team_modeop functions and use them in modes 2013-03-06 14:55:20 -05:00
team_mode_loadbalance.c net: filter: split 'struct sk_filter' into socket and bpf parts 2014-08-02 15:03:58 -07:00
team_mode_random.c random32: add prandom_u32_max and convert open coded users 2014-01-21 23:17:20 -08:00
team_mode_roundrobin.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2013-06-19 16:49:39 -07:00