Re: [PATCH 6/7] mm: kill vma flag VM_EXECUTABLE

[Konstantin Khlebnikov <khlebnikov@openvz.org>]

Linus Torvalds wrote:
> On Thu, Apr 5, 2012 at 2:44 PM, Matt Helsley<matthltc@us.ibm.com>  wrote:
>>
>> I don't think the definition of an ABI is whether there's documentation
>> for it. It's whether the interface is used or not. At least that's the
>> impression I've gotten from reading Linus' rants over the years.
>
> Yes.
>
> That said, I *do* have some very dim memory of us having had real
> issues with the /proc/<pid>/exe thing and having regressions due to
> holding refcounts to executables that were a.out binaries and not
> demand-loaded. And people wanting to unmount filesystems despite the
> binaries being live.
>
> That said, I suspect that whatever issues we used to have with that
> are pretty long gone. I don't think people use non-mmap'ed binaries
> any more. So I think we can try it and see. And revert if somebody
> actually notices and has problems.

Instead of tracking count of vma with VM_EXECUTABLE bit we can track
count of vma with vma->vm_file == mm->exe_file, this will be nearly
the same behaviour. This was in early version of my patch, but I prefer
to go deeper. So, we can revert it without introducing VM_EXECUTABLE again.

>
>                      Linus

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