Canadian traveling to Nepal via china, do we need chin ease visa?

Vancouver/Shanghai (PVG)/Kunming (KMG)/Kathmandu. my first stop is in Shanghai with transit time (~3 hours), second transit is in Kunming (about 2 hours), Canadian passport. for this route should I need entry permit before I begin my journey?

Similarly when I come back from Nepal, my route is Kathmandu> Kunming (KMG)>Nanjing (NKG)
>Vancouver; My transit is about 12 hours in Kunming, 2 hours stop in Nanjing. for this time, should I take Chinese visa or can I use 24 hours transit for two stops but less than 24 hours stay in China?