[SCSI] transport_class: BUG if we can't release the attribute container

Every current transport class calls transport_container_release but
ignores the return value.  This is catastrophic if it returns an error
because the containers are part of a global list and the next action of
almost every transport class is to free the memory used by the
container.

Fix this by making transport_container_release a void, but making it BUG
if attribute_container_release returns an error ... this catches the
root cause of a system panic much earlier.  If we don't do this, we get
an eventual BUG when the attribute container list notices the corruption
caused by the freed memory it's still referencing.

Also made attribute_container_release __must_check as a reminder.

Cc: Greg KH <greg@kroah.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>

2 files changed, 3 insertions, 2 deletions

diff --git a/drivers/base/transport_class.c b/drivers/base/transport_class.c
index 40bca48abc12..cabd0edf2156 100644
--- a/drivers/base/transport_class.c
+++ b/drivers/base/transport_class.c
@@ -108,7 +108,8 @@ EXPORT_SYMBOL_GPL(anon_transport_class_register);
  */
 void anon_transport_class_unregister(struct anon_transport_class *atc)
 {
-        attribute_container_unregister(&atc->container);
+        if (unlikely(attribute_container_unregister(&atc->container)))
+                BUG();
 }
 EXPORT_SYMBOL_GPL(anon_transport_class_unregister);
 
diff --git a/drivers/scsi/raid_class.c b/drivers/scsi/raid_class.c
index 86e13183c9ba..52182a744ba6 100644
--- a/drivers/scsi/raid_class.c
+++ b/drivers/scsi/raid_class.c
@@ -289,7 +289,7 @@ raid_class_release(struct raid_template *r)
 {
         struct raid_internal *i = to_raid_internal(r);
 
-        attribute_container_unregister(&i->r.raid_attrs.ac);
+        BUG_ON(attribute_container_unregister(&i->r.raid_attrs.ac));
 
         kfree(i);
 }