Messages in this thread | | | Date | Sat, 4 Mar 2023 00:04:30 +0100 | From | Michal Koutný <> | Subject | Re: [PATCH] x86/mm: Do not shuffle CPU entry areas without KASLR |
| |
On Fri, Mar 03, 2023 at 01:24:53PM -0800, Dave Hansen <dave.hansen@intel.com> wrote: > Should this be kaslr_memory_enabled() or kaslr_enabled()?
Originally, I had chosen kaslr_enabled(), seeing the PGD requirement of KASAN (whole randomization area CPU_ENTRY_AREA_MAP_SIZE would fit in PGD afterall).
> The delta seems to be CONFIG_KASAN, and the cpu entry area randomization > works just fine with KASAN after some recent fixes.
But then I found KASAN code trying to be smart and having the fixups, hence I chickened out to kaslr_memory_enabled().
> I _think_ that makes cpu entry area randomization more like module > randomization which would point toward kaslr_enabled().
<del>I understood the only difference between kaslr_enabled and kaslr_memory_enabled is the PGD alignment of the respective regions. (Although, I don't see where KASAN breaks with unaligned ranges except for better efficiency of page tables.)</del>
I've just found your [1], wondering the similar.
That being said, I will send v2 with just kaslr_enabled() guard and updated commit message to beware of KASAN fixups (when backporting).
Thanks, Michal
[1] https://lore.kernel.org/r/299fbb80-e3ab-3b7c-3491-e85cac107930@intel.com/
| |