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

[Mike Kravetz]

On 09/17/2017 06:52 PM, Jann Horn wrote:
> On Fri, Sep 15, 2017 at 2:37 PM, Mike Kravetz <mike.kravetz@xxxxxxxxxx> wrote:
> [...]
>> A recent change was made to mremap so that an attempt to create a
>> duplicate a private mapping will fail.
>>
>> commit dba58d3b8c5045ad89c1c95d33d01451e3964db7
>> Author: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
>> Date:   Wed Sep 6 16:20:55 2017 -0700
>>
>>     mm/mremap: fail map duplication attempts for private mappings
>>
>> This return code is also documented here.
> [...]
>> diff --git a/man2/mremap.2 b/man2/mremap.2
> [...]
>> @@ -174,7 +189,12 @@ and
>>  or
>>  .B MREMAP_FIXED
>>  was specified without also specifying
>> -.BR MREMAP_MAYMOVE .
>> +.BR MREMAP_MAYMOVE ;
>> +or \fIold_size\fP was zero and \fIold_address\fP does not refer to a
>> +private anonymous mapping;
> 
> Shouldn't this be the other way around? "or old_size was zero and
> old_address refers to a private anonymous mapping"?

Thanks Jann,

Yes that is wrong.  In addition, the description of this functionality
in the section before this is also incorrect.

I will fix both in a new version of the patch.

-- 
Mike Kravetz