Re: [PATCH RESEND 0/8] Fix mmap base in bottom-up mmap

[Helge Deller <deller@gmx.de>]

On 26.08.19 09:34, Alexandre Ghiti wrote:
> On 6/20/19 7:03 AM, Alexandre Ghiti wrote:
>> This series fixes the fallback of the top-down mmap: in case of
>> failure, a bottom-up scheme can be tried as a last resort between
>> the top-down mmap base and the stack, hoping for a large unused stack
>> limit.
>>
>> Lots of architectures and even mm code start this fallback
>> at TASK_UNMAPPED_BASE, which is useless since the top-down scheme
>> already failed on the whole address space: instead, simply use
>> mmap_base.
>>
>> Along the way, it allows to get rid of of mmap_legacy_base and
>> mmap_compat_legacy_base from mm_struct.
>>
>> Note that arm and mips already implement this behaviour.
>>
>> Alexandre Ghiti (8):
>>    s390: Start fallback of top-down mmap at mm->mmap_base
>>    sh: Start fallback of top-down mmap at mm->mmap_base
>>    sparc: Start fallback of top-down mmap at mm->mmap_base
>>    x86, hugetlbpage: Start fallback of top-down mmap at mm->mmap_base
>>    mm: Start fallback top-down mmap at mm->mmap_base
>>    parisc: Use mmap_base, not mmap_legacy_base, as low_limit for
>>      bottom-up mmap
>>    x86: Use mmap_*base, not mmap_*legacy_base, as low_limit for bottom-up
>>      mmap
>>    mm: Remove mmap_legacy_base and mmap_compat_legacy_code fields from
>>      mm_struct
>>
>>   arch/parisc/kernel/sys_parisc.c  |  8 +++-----
>>   arch/s390/mm/mmap.c              |  2 +-
>>   arch/sh/mm/mmap.c                |  2 +-
>>   arch/sparc/kernel/sys_sparc_64.c |  2 +-
>>   arch/sparc/mm/hugetlbpage.c      |  2 +-
>>   arch/x86/include/asm/elf.h       |  2 +-
>>   arch/x86/kernel/sys_x86_64.c     |  4 ++--
>>   arch/x86/mm/hugetlbpage.c        |  7 ++++---
>>   arch/x86/mm/mmap.c               | 20 +++++++++-----------
>>   include/linux/mm_types.h         |  2 --
>>   mm/debug.c                       |  4 ++--
>>   mm/mmap.c                        |  2 +-
>>   12 files changed, 26 insertions(+), 31 deletions(-)
>>
>
> Any thoughts about that series ? As said before, this is just a preparatory patchset in order to
> merge x86 mmap top down code with the generic version.

I just tested your patch series successfully on the parisc
architeture. You may add:

Tested-by: Helge Deller <deller@gmx.de> # parisc

Thanks!
Helge