From 3db096011722fd8717e57687ae94b6917a11c9cc Mon Sep 17 00:00:00 2001 From: Jon Maloy Date: Mon, 18 Dec 2017 20:03:05 +0100 Subject: tipc: fix list sorting bug in function tipc_group_update_member() When, during a join operation, or during message transmission, a group member needs to be added to the group's 'congested' list, we sort it into the list in ascending order, according to its current advertised window size. However, we miss the case when the member is already on that list. This will have the result that the member, after the window size has been decremented, might be at the wrong position in that list. This again may have the effect that we during broadcast and multicast transmissions miss the fact that a destination is not yet ready for reception, and we end up sending anyway. From this point on, the behavior during the remaining session is unpredictable, e.g., with underflowing window sizes. We now correct this bug by unconditionally removing the member from the list before (re-)sorting it in. Signed-off-by: Jon Maloy Signed-off-by: David S. Miller --- net/tipc/group.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) (limited to 'net/tipc/group.c') diff --git a/net/tipc/group.c b/net/tipc/group.c index b96ec429bb9b..bbc004eaa31a 100644 --- a/net/tipc/group.c +++ b/net/tipc/group.c @@ -351,8 +351,7 @@ void tipc_group_update_member(struct tipc_member *m, int len) if (m->window >= ADV_IDLE) return; - if (!list_empty(&m->congested)) - return; + list_del_init(&m->congested); /* Sort member into congested members' list */ list_for_each_entry_safe(_m, tmp, &grp->congested, congested) { -- cgit v1.2.3