Be aware that if your institution uses some sort of authentication service this process might be less straight forward. You might have to take session cookies into account (eg. close your window). Otherwise you will find yourself logged in, even after you have "logged out".
As JozAa advised it is always advisable to close the entire browser that you used to access Canvas with, as often your authentication will be associated with a browser session. Your Canvas login session credentials can persist in the browser (regardless of how many tabs you have open and/or the content you are accessing) until that browser session ends. It may look like you have logged out successfully but the session and the access token for that session does not cease until the browser is closed fully. This is especially pertinent when using shared devices.