MFC r266444:

  We have two functions from where a geom orphan method could be called:
  g_orphan_register and g_resize_provider_event. Both are called from the
  event queue. Also we have GEOM_DEV class, which does deferred destroy
  for its consumers via g_dev_destroy (also called from the event queue).
  So it is possible, that for some consumers an orphan method will be
  called twice. This triggers panic in g_dev_orphan.
  Check that consumer isn't already orphaned before call orphan method.

1 files changed, 8 insertions, 0 deletions

diff --git a/sys/geom/geom_event.c b/sys/geom/geom_event.c
index 3a1363e..2ded638 100644
--- a/sys/geom/geom_event.c
+++ b/sys/geom/geom_event.c
@@ -206,6 +206,14 @@ g_orphan_register(struct g_provider *pp)
 		KASSERT(cp->geom->orphan != NULL,
 		    ("geom %s has no orphan, class %s",
 		    cp->geom->name, cp->geom->class->name));
+		/*
+		 * XXX: g_dev_orphan method does deferred destroying
+		 * and it is possible, that other event could already
+		 * call the orphan method. Check consumer's flags to
+		 * do not schedule it twice.
+		 */
+		if (cp->flags & G_CF_ORPHAN)
+			continue;
 		cp->flags |= G_CF_ORPHAN;
 		cp->geom->orphan(cp);
 	}