Re: [PATCH] arm64: correct modules range of kernel virtual memory layout

From: Will Deacon
Date: Mon Aug 07 2017 - 09:16:13 EST


On Mon, Aug 07, 2017 at 07:04:46PM +0800, Miles Chen wrote:
> The commit f80fb3a3d508 ("arm64: add support for kernel ASLR")
> moved module virtual address to
> [module_alloc_base, module_alloc_base + MODULES_VSIZE).
>
> Display module information of the virtual kernel
> memory layout by using module_alloc_base.
>
> testing output:
> 1) Current implementation:
> Virtual kernel memory layout:
> modules : 0xffffff8000000000 - 0xffffff8008000000 ( 128 MB)
> 2) this patch + KASLR:
> Virtual kernel memory layout:
> modules : 0xffffff8000560000 - 0xffffff8008560000 ( 128 MB)
> 3) this patch + KASLR and a dummy seed:
> Virtual kernel memory layout:
> modules : 0xffffffa7df637000 - 0xffffffa7e7637000 ( 128 MB)
>
> Signed-off-by: Miles Chen <miles.chen@xxxxxxxxxxxx>
> ---
> arch/arm64/mm/init.c | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)

Does this mean the modules code in our pt dumper is busted
(arch/arm64/mm/dump.c)? Also, what about KASAN, which uses these addresses
too (in kasan_init)? Should we just remove MODULES_VADDR and MODULES_END
altogether?

Will