Messages in this thread | | | From | Linus Torvalds <> | Date | Tue, 7 Apr 2020 14:30:56 -0700 | Subject | Re: [PATCH v3] mm: Add kvfree_sensitive() for freeing sensitive data objects |
| |
On Tue, Apr 7, 2020 at 2:25 PM Uladzislau Rezki <urezki@gmail.com> wrote: > > Seems like there is only one place where we can "sleep". I mean when we > call vfree(). That is free_vmap_area_noflush() -> try_purge_vmap_area_lazy(). > Basically try_purge_vmap_area_lazy() can call the schedule() what is not > allowed for IRQs. Instead of inlining the try_purge_vmap_area_lazy() > into current context we can schedule_work(). And i think it makes sense > from many point of views.
I don't think that's the only case.
Or rather, that may be the only case of _sleeping_, but we also aren't irq-safe wrt locking.
And I'm not just talking about the vmap_purge_lock mutex, but all the spinlocks etc we have.
That said, I haven't looked at that code in _ages_. Maybe those things would be trivial to just turn into irq-safe ones and there are no real latency issues anywhere.
Linus
| |