Patch "target: Don't BUG_ON during NodeACL dynamic -> explicit conversion" has been added to the 4.4-stable tree

This is a note to let you know that I've just added the patch titled

    target: Don't BUG_ON during NodeACL dynamic -> explicit conversion

to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
target-don-t-bug_on-during-nodeacl-dynamic-explicit-conversion.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Nicholas Bellinger <[email protected]>
Date: Sun, 23 Oct 2016 14:28:15 -0700
Subject: target: Don't BUG_ON during NodeACL dynamic -> explicit conversion

From: Nicholas Bellinger <[email protected]>

commit 391e2a6de9781e4906dd7e0b1cc097050bf43e11 upstream.

After the v4.2+ RCU conversion to se_node_acl->lun_entry_hlist, a BUG_ON() was added in core_enable_device_list_for_node() to detect when the located orig->se_lun_acl contains an existing se_lun_acl pointer reference.

However, this scenario can happen when a dynamically generated NodeACL is being converted to an explicit NodeACL, when the explicit NodeACL contains a different LUN mapping than the default provided by the WWN endpoint.

So instead of triggering BUG_ON(), go ahead and fail instead following the original pre RCU conversion logic.

---
 drivers/target/target_core_device.c |   10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

@@ -362,7 +362,15 @@ int core_enable_device_list_for_node(
 			kfree(new);
 			return -EINVAL;
 		}
-		BUG_ON(orig->se_lun_acl != NULL);
+		if (orig->se_lun_acl != NULL) {
+			pr_warn_ratelimited("Detected existing explicit"
+				" se_lun_acl->se_lun_group reference for %s"
+				" mapped_lun: %llu, failing\n",
+				 nacl->initiatorname, mapped_lun);
+			mutex_unlock(&nacl->lun_entry_mutex);
+			kfree(new);
+			return -EINVAL;
+		}
 
 		rcu_assign_pointer(new->se_lun, lun);
 		rcu_assign_pointer(new->se_lun_acl, lun_acl);

Patches currently in stable-queue which might be from [email protected] are

queue-4.4/target-fix-compare_and_write-ref-leak-for-non-good-status.patch queue-4.4/target-use-correct-scsi-status-during-extended_copy-exception.patch queue-4.4/target-don-t-bug_on-during-nodeacl-dynamic-explicit-conversion.patch queue-4.4/target-fix-early-transport_generic_handle_tmr-abort-scenario.patch