Hi Huacai,
On Sat, Oct 20, 2018 at 09:01:31PM +0800, Huacai Chen wrote:
> By the way, not all VDSO_RANDOMIZE_SIZE can be used for vdso_base()
> randomization because VDSO need some room to locate itself (in this
> patch we reserve 64KB).
>
>%
>
> diff --git a/arch/mips/kernel/vdso.c b/arch/mips/kernel/vdso.c
> index 48a9c6b..d6232d9 100644
> --- a/arch/mips/kernel/vdso.c
> +++ b/arch/mips/kernel/vdso.c
> @@ -106,7 +106,7 @@ static unsigned long vdso_base(void)
> base = STACK_TOP + PAGE_SIZE;
>
> if (current->flags & PF_RANDOMIZE) {
> - base += get_random_int() & (VDSO_RANDOMIZE_SIZE - 1);
> + base += get_random_int() & (VDSO_RANDOMIZE_SIZE - SZ_64K - 1);
> base = PAGE_ALIGN(base);
> }
This change in v2 is unnecessary - STACK_TOP already accounts for the
size of the VDSO, so we don't need to leave space for it a second time
here.
v1 of your patch is in mips-fixes, which I'll submit a pull request for
soon.
Thanks,
Paul
