Messages in this thread | | | Date | Sun, 26 Oct 2014 11:16:10 -0700 | Subject | Re: vmalloced stacks on x86_64? | From | Linus Torvalds <> |
| |
On Sat, Oct 25, 2014 at 4:16 PM, Andy Lutomirski <luto@amacapital.net> wrote: > > On brief inspection, grsecurity isn't actually vmallocing the stack. > It seems to be allocating it the normal way and then vmapping it. > That allows it to modify sg_set_buf to work on stack addresses (sigh).
Perhaps more importantly, the vmalloc space is a limited resource (at least on 32-bit), and using vmap probably results in less fragmentation.
I don't think either is really even an option on 32-bit due to the limited address space. On 64-bit, maybe a virtually remapped stack would be ok.
Linus
| |