Re: [PATCH v1 0/3] perf/binfmt/mm: remove in-tree usage of MAP_EXECUTABLE

David Hildenbrand
2021-04-21T20:56:21Z

On 21.04.21 21:03, Eric W. Biederman wrote:
> David Hildenbrand <david@redhat.com> writes:
>
>> Stumbling over the history of MAP_EXECUTABLE, I noticed that we still
>> have some in-tree users that we can get rid of.
>>
>> A good fit for the whole series could be Andrew's tree.
>
> In general this looks like a good cleanup.
>
> Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
>
> As far as I can see we can go after MAP_DENYWRITE the same way.
> Today deny_write_access in open_exec is what causes -ETXTBSY
> when attempting to write to file that is current executing.
>
> Do you have any plans to look at that?

I did have a look and thought about ripping out MAP_DENYWRITE; I'm still
in the process of connecting the pieces.

Some VM_DENYWRITE e.g., in mm/khugepaged.c still gives me a headache ,
and I'll have to double-check whether it would be okay to just fallback
on checking the actual vm->file.

--
Thanks,

David / dhildenb