Re: [PATCH v17 08/10] PM: hibernate: disable when there are active secretmem users

On Mon 08-02-21 11:32:11, David Hildenbrand wrote: > On 08.02.21 11:18, Michal Hocko wrote: >> On Mon 08-02-21 10:49:18, Mike Rapoport wrote: >>> From: Mike Rapoport <rppt(a)linux.ibm.com&gt; >>> >>> It is unsafe to allow saving of secretmem areas to the hibernation >>> snapshot as they would be visible after the resume and this essentially >>> will defeat the purpose of secret memory mappings. >>> >>> Prevent hibernation whenever there are active secret memory users. >> >> Does this feature need any special handling? As it is effectivelly >> unevictable memory then it should behave the same as other mlock, ramfs >> which should already disable hibernation as those cannot be swapped out, >> no? >> > > Why should unevictable memory not go to swap when hibernating? We're merely > dumping all of our system RAM (including any unmovable allocations) to swap > storage and the system is essentially completely halted. > My understanding is that mlock is never really made visible via swap storage.