ocfs2: fix a use after free on error

The error handling in this function frees "reg" but it is still on the
"o2hb_all_regions" list so it will lead to a use after freew.  Joseph Qi
points out that we need to clear the bit in the "o2hb_region_bitmap" as
well

Link: https://lkml.kernel.org/r/YBk4M6HUG8jB/jc7@mwanda
Fixes: 1cf257f ("ocfs2: fix memory leak")
Signed-off-by: Dan Carpenter <[email protected]>
Reviewed-by: Joseph Qi <[email protected]>
Cc: Mark Fasheh <[email protected]>
Cc: Joel Becker <[email protected]>
Cc: Junxiao Bi <[email protected]>
Cc: Changwei Ge <[email protected]>
Cc: Gang He <[email protected]>
Cc: Jun Piao <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

fs/ocfs2/cluster/heartbeat.c

@@ -2042,7 +2042,7 @@ static struct config_item *o2hb_heartbeat_group_make_item(struct config_group *g
 			o2hb_nego_timeout_handler,
 			reg, NULL, &reg->hr_handler_list);
 	if (ret)
-		goto free;
+		goto remove_item;
 
 	ret = o2net_register_handler(O2HB_NEGO_APPROVE_MSG, reg->hr_key,
 			sizeof(struct o2hb_nego_msg),
@@ -2057,6 +2057,12 @@ static struct config_item *o2hb_heartbeat_group_make_item(struct config_group *g
 
 unregister_handler:
 	o2net_unregister_handler_list(&reg->hr_handler_list);
+remove_item:
+	spin_lock(&o2hb_live_lock);
+	list_del(&reg->hr_all_item);
+	if (o2hb_global_heartbeat_active())
+		clear_bit(reg->hr_region_num, o2hb_region_bitmap);
+	spin_unlock(&o2hb_live_lock);
 free:
 	kfree(reg);
 	return ERR_PTR(ret);