BUG/MEDIUM: connections: Hold the lock when wanting to kill a connection.
In connect_server(), when we decide we want to kill the connection of
another thread because there are too many idle connections, hold the
toremove_lock of the corresponding thread, othervise, there's a small race
condition where we could try to add the connection to the toremove_connections
list while it has already been free'd.
This should be backported to 2.0 and 2.1.
(cherry picked from commit 140237471e408736bb7162e68c572c710a66a526)
Signed-off-by: Christopher Faulet <cfaulet@haproxy.com>
(cherry picked from commit 000f227a4cfdb019575e889638f9e0e5a53bbb0b)
Signed-off-by: Christopher Faulet <cfaulet@haproxy.com>
diff --git a/src/backend.c b/src/backend.c
index c80dc0f..487a7c2 100644
--- a/src/backend.c
+++ b/src/backend.c
@@ -1362,6 +1362,7 @@
// see it possibly larger.
ALREADY_CHECKED(i);
+ HA_SPIN_LOCK(OTHER_LOCK, &toremove_lock[tid]);
tokill_conn = LIST_POP_LOCKED(&srv->idle_orphan_conns[i],
struct connection *, list);
if (tokill_conn) {
@@ -1372,6 +1373,7 @@
task_wakeup(idle_conn_cleanup[i], TASK_WOKEN_OTHER);
break;
}
+ HA_SPIN_UNLOCK(OTHER_LOCK, &toremove_lock[tid]);
}
}