Re: [patch v2] mremap.2: Add description of old_size == 0 functionality

[Michael Kerrisk (man-pages)]

Hi Mike,

On 25 September 2017 at 18:33, Mike Kravetz <mike.kravetz@xxxxxxxxxx> wrote:
> On 09/20/2017 12:25 AM, Michael Kerrisk (man-pages) wrote:

[...]

>> I've applied this, and added Reviewed-by tags for Florian and Jann.
>> But, I think it's also worth noting the older, now disallowed, behavior,
>> and why the behavior was changed. So I added a note in BUGS:
>>
>>     BUGS
>>        Before Linux 4.14, if old_size was zero and the  mapping  referred
>>        to  by  old_address  was  a private mapping (mmap(2) MAP_PRIVATE),
>>        mremap() created a new private mapping unrelated to  the  original
>>        mapping.   This behavior was unintended and probably unexpected in
>>        user-space applications (since the intention  of  mremap()  is  to
>>        create  a new mapping based on the original mapping).  Since Linux
>>        4.14, mremap() fails with the error EINVAL in this scenario.
>>
>> Does that seem okay?
>
> Sorry for the late reply Michael,  I've been away for a few days.
>
> Yes, the above seems okay.  Thanks for your help with this.

You're welcome. Thanks for checking it over!

Cheers,

Michael

-- 
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Linux/UNIX System Programming Training: http://man7.org/training/