From: Jiri Pirko Date: Wed, 14 Jan 2015 17:15:30 +0000 (+0100) Subject: team: avoid possible underflow of count_pending value for notify_peers and mcast_rejoin X-Git-Tag: omap-for-v4.1/prcm-dts-mfd-syscon-fix~280^2~1 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=b0d11b42785b70e19bc6a3122eead3f7969a7589;p=pandora-kernel.git 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 Signed-off-by: Jiri Benc Signed-off-by: David S. Miller --- Reading git-diff-tree failed