Comment # 1 on bug 1165946 from Frank Kruger

I recently experienced the same issue, which is solved for me by kernel 5.5.8
from the kernel stable repo. In fact, it contains:

commit 3d6cf5c75ea54d338df3d89f2da56b98d4812011
Author: Chao Yu <chao@kernel.org>
Date:   Fri Dec 27 18:44:56 2019 +0800
f2fs: fix to add swap extent correctly    
commit 3e5e479a39ce9ed60cd63f7565cc1d9da77c2a4e upstream.