Created attachment 1071046 [details]
7.1.z-bz1260719-1-quorum-don-t-allow-quorum_trackstart-to-be-called-tw

quorum: don't allow quorum_trackstart to be called twice

If quorum_trackstart() or votequorum_trackstart() are called twice with
CS_TRACK_CHANGES then the client gets added twice to the notifications
list effectively corrupting it. Users have reported segfaults in
corosync when they did this (by mistake!).

As there's already a tracking_enabled flag in the private-data, we check
that before adding to the list again and return an error if
the process is already registered.

Signed-off-by: Christine Caulfield <ccaulfie>
Reviewed-by: Jan Friesse <jfriesse>

Created attachment 1071047 [details]
7.1.z-bz1260719-2-votequorum-Fix-auto_tie_breaker-behaviour-in-odd-siz

votequorum: Fix auto_tie_breaker behaviour in odd-sized clusters

auto_tie_breaker can behave incorrectly in the case of a cluster
with an odd number of nodes. It's possible for a partition to
have quorum while the other side has the ATB node, and both will
continue working. (Of course in a properly configured cluster one side
will be fenced but that becomes an indeterminate race .. just what ATB
is supposed to avoid).

This patch prevents ATB from running in a partition if the 'other'
partition might have quorum, and also mandates the use of wait_for_all
in clusters with an odd number of nodes so that a quorate partition
cannot start services or fence an existing partition with the tie
breaker node.

Signed-Off-By: Christine Caulfield <ccaulfie>
Reviewed-by: Jan Friesse <jfriesse>

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://rhn.redhat.com/errata/RHBA-2015-1789.html