Re: [PATCH v6 0/8] ipc: Clamp *mni to the real IPCMNI limit & increase that limit

[Waiman Long]

On 05/02/2018 11:06 AM, Eric W. Biederman wrote:
>
>>> and or users that may or may not exist.  If you can find something that
>>> will care sure.  We need to avoid breaking userspace and causing
>>> regressions.  However as this stands it looks you are making maintenance
>>> of the kernel more difficult to avoid having to look to see if there are
>>> monsters under the bed.
>> I shall admit that it can be hard to find applications that will
>> explicitly need that as we usually don't have access to the applications
>> that the customers have. It is more a correctness issue where the
>> existing code is kind of lying about what can actually be supported. I
>> just want to make the users more aware of what the right limits are.
> You presume the kernel is lying to applications.  I admit the kernel
> can lie to applications.  I don't see any evidence that the kernel is
> actually doing so.  So far (to me) it looks like a large number of sysv
> shared memory segments is not particulalry common.
>
> So I would not be at all surprised if no regressions would be generated
> if you simply deny setting the value past the maximum.

Maybe you are right. I will update the patchset to fail the update if
the range is exceeded since I had added option of extending the limit if
the users choose to do so.

Cheers,
Longman