Re: [PATCH bpf-next 1/3] mm/vmalloc: introduce vmalloc_exec which allocates RO+X memory

Song Liu
2022-07-15T00:25:09Z

> On Jul 14, 2022, at 11:15 AM, Uladzislau Rezki <urezki@gmail.com> wrote:
>
> On Thu, Jul 14, 2022 at 04:54:40AM +0000, Song Liu wrote:
>>
>>
>>> On Jul 13, 2022, at 9:23 PM, Christoph Hellwig <hch@infradead.org> wrote:
>>>
>>> On Wed, Jul 13, 2022 at 03:49:45PM +0000, Song Liu wrote:
>>>>
>>>>
>>>>> On Jul 13, 2022, at 3:08 AM, Christoph Hellwig <hch@infradead.org> wrote:
>>>>>
>>>>> NAK. This is not something that should be an exported public API
>>>>> ever.
>>>>
>>>> Hmm.. I will remove EXPORT_SYMBOL_GPL (if we ever do a v2 of this..)
>>>
>>> Even without that it really is not a vmalloc API anyway.
>>
>> This ...
>>
>>> Executable
>>> memory needs to be written first, so we should allocate it in that state
>>> and only mark it executable after that write has completed.
>>
>> ... and this are two separate NAKs.
>>
>> For the first NAK, I agree that my version is another layer on top of
>> vmalloc. But what do you think about Peter's idea? AFAICT, that fits
>> well in vmalloc logic.
>>
> I am not able to find the patch/change to see what you have done.

vger dropped my patch again. :(

> But
> please do not build a new allocator on top of vmalloc code. We have
> three different ones what make things to be complicated :)

It was a bpf_prog_pack like allocator, but named as vmalloc_exec(),
vfree_exec(). I guess I have got enough NAKs for it.

Thanks,
Song