Re: [PATCH 6/6] mm: Forbid splitting special mappings

[Dmitry Safonov]

On 1/22/21 1:00 PM, Will Deacon wrote:
> On Fri, Jan 22, 2021 at 12:58:58PM +0000, Will Deacon wrote:
>> On Tue, Oct 13, 2020 at 02:34:16AM +0100, Dmitry Safonov wrote:
>>> Don't allow splitting of vm_special_mapping's.
>>> It affects vdso/vvar areas. Uprobes have only one page in xol_area so
>>> they aren't affected.
>>>
>>> Those restrictions were enforced by checks in .mremap() callbacks.
>>> Restrict resizing with generic .split() callback.
>>>
>>> Signed-off-by: Dmitry Safonov <dima@xxxxxxxxxx>
>>> ---
>>>  arch/arm/kernel/vdso.c    |  9 ---------
>>>  arch/arm64/kernel/vdso.c  | 41 +++------------------------------------
>>>  arch/mips/vdso/genvdso.c  |  4 ----
>>>  arch/s390/kernel/vdso.c   | 11 +----------
>>>  arch/x86/entry/vdso/vma.c | 17 ----------------
>>>  mm/mmap.c                 | 12 ++++++++++++
>>>  6 files changed, 16 insertions(+), 78 deletions(-)
>>
>> For arm64:
>>
>> Acked-by: Will Deacon <will@xxxxxxxxxx>
> 
> Wait -- this got merged ages ago! Why am I reading such old email?

It's alright, thanks for looking at this again!

-- 
          Dmitry