CVE-2017-1000405: Concurrent Execution using Shared Resource with Improper Synchronization

The Linux Kernel versions 2.6.38 through 4.14 have a problematic use of pmdmkdirty in the touchpmd function inside the THP implementation. touchpmd can be reached by getuserpages. In such case, the pmd will become dirty. This scenario breaks the new canfollowwritepmd's logic - pmd can become dirt...