In gossiper::handle_major_state_change() we set the endpoint_state for
a particular endpoint and replicate the changes to other cores.
This is totally unsynchronized with the execution of
gossiper::evict_from_membership(), which can happen concurrently, and
can remove the very same endpoint from the map (in all cores).
Replicating the changes to other cores in handle_major_state_change()
can interleave with replicating the changes to other cores in
evict_from_membership(), and result in an undefined final state.
Another issue happened in debug mode dtests, where a fiber executes
handle_major_state_change(), calls into the subscribers, of which
storage_service is one, and ultimately lands on
storage_service::update_peer_info(), which iterates over the
endpoint's application state with deferring points in between (to
update a system table). gossiper::evict_from_membership() was executed
concurrently by another fiber, which freed the state the first one is
iterating over.
Fixes#3299.
Signed-off-by: Duarte Nunes <duarte@scylladb.com>
Message-Id: <20180318123211.3366-1-duarte@scylladb.com>
(cherry picked from commit 810db425a5)
0a561fc326