[PATCH] ocfs2: Fix a use after free on error

[Dan Carpenter]

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 free.  The fix
for this is to only add it to the list after everything has succeeded.

Fixes: 1cf257f51191 ("ocfs2: fix memory leak")
Signed-off-by: Dan Carpenter <dan.carpen...@oracle.com>
---
This is from static analysis and hasn't been tested.

 fs/ocfs2/cluster/heartbeat.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/fs/ocfs2/cluster/heartbeat.c b/fs/ocfs2/cluster/heartbeat.c
index 0179a73a3fa2..92af4dc813e7 100644
--- a/fs/ocfs2/cluster/heartbeat.c
+++ b/fs/ocfs2/cluster/heartbeat.c
@@ -2025,7 +2025,6 @@ static struct config_item 
*o2hb_heartbeat_group_make_item(struct config_group *g
                }
                set_bit(reg->hr_region_num, o2hb_region_bitmap);
        }
-       list_add_tail(&reg->hr_all_item, &o2hb_all_regions);
        spin_unlock(&o2hb_live_lock);
 
        config_item_init_type_name(&reg->hr_item, name, &o2hb_region_type);
@@ -2053,6 +2052,10 @@ static struct config_item 
*o2hb_heartbeat_group_make_item(struct config_group *g
 
        o2hb_debug_region_init(reg, o2hb_debug_dir);
 
+       spin_lock(&o2hb_live_lock);
+       list_add_tail(&reg->hr_all_item, &o2hb_all_regions);
+       spin_unlock(&o2hb_live_lock);
+
        return &reg->hr_item;
 
 unregister_handler:
-- 
2.29.2