DEBUG: don't load librados at module import in dashboard

Signed-off-by: John Spray <john.spray@redhat.com>

src/pybind/mgr/dashboard/module.py

@@ -32,9 +32,6 @@ def global_instance():
 from types import OsdMap, NotFound, Config, FsMap, MonMap, \
     PgSummary, Health, MonStatus
 
-import rados
-import rbd_iscsi
-import rbd_mirroring
 from rbd_ls import RbdLs, RbdPoolLs
 from cephfs_clients import CephFSClients
 from rgw import RGWDaemons
@@ -125,6 +122,13 @@ def __init__(self, *args, **kwargs):
         self.log_buffer = collections.deque(maxlen=LOG_BUFFER_SIZE)
         self.audit_buffer = collections.deque(maxlen=LOG_BUFFER_SIZE)
 
+        # Import Ceph bindings at construction time rather than import time,
+        # for debugging weird lockdep crashes during import
+        # (https://github.com/ceph/ceph/pull/19235/files)
+        import rados
+        import rbd_iscsi
+        import rbd_mirroring
+
         # Keep a librados instance for those that need it.
         self._rados = None
 

src/pybind/mgr/dashboard/rbd_ls.py

@@ -1,6 +1,4 @@
 
-import rbd
-import rados
 from types import OsdMap
 from remote_view_cache import RemoteViewCache
 
@@ -27,10 +25,14 @@ def _init(self):
         self.log.debug("Constructing IOCtx")
         self.ioctx = self._module.rados.open_ioctx(self.pool)
 
+        import rbd
+
         self.log.debug("Constructing RBD")
         self.rbd = rbd.RBD()
 
     def _get(self):
+        import rbd
+
         self.log.debug("rbd.list")
         names = self.rbd.list(self.ioctx)
         result = []
@@ -54,6 +56,8 @@ def _get(self):
         return result
 
     def _format_bitmask(self, features):
+        import rbd
+
         names = ""
         RBD_FEATURES_NAME_MAPPING = {
             rbd.RBD_FEATURE_LAYERING: "layering",