The Dirty COW vulnerability (CVE-20165195) is one of the most hyped and branded vulnerabilities published. Despite the enormous publicity the bug had received, Bindecy discovered that the patch was incomplete. The vulnerability was in the get_user_pages function used to get the physical pages behind virtual addresses in user processes. The call to faultin_page was introduced in a new function called followpage. The following fix introduced a new fix in the function.”]
Source: https://medium.com/bindecy/huge-dirty-cow-cve-2017-1000405-110eca132de0