Unfortunately a HKSAR passport is an irrelevant document inside Mainland China. A HK resident of Chinese nationality is required to use a Huixiangzheng (literally Mainland Travel Permit, commonly known by its former name Home Return Permit) to enter, exit, or even transit Mainland China. (Or replacement documents such as Lüxingzheng [Travel Permit].) The requirement is quite clearly posted on TIMATIC and Air China's various websites.

With the consular agreement between China and Canada, there will be no problems using a Canadian passport and be treated accordingly as a Canadian. The only possible difference is being asked your Chinese name so they can verify against your possibly other entries on their database using other "Chinese" documents. This has been reported by many Americans and Canadians who are ethnic Chinese born on "Chinese" soil.