On 03/26/2018 10:47 AM, Shuah Khan wrote: > > Also what happens "pkey_free() pkey-0" - can you elaborate more on that > "silliness consequences" It's just what happens if you free any other pkey that is in use: it might get reallocated later. The most likely scenario is that you will get pkey-0 back from pkey_alloc(), you will set an access-disable or write-disable bit in PKRU for it, and your next stack access will SIGSEGV.