[Devel] Re: [PATCH 11/13] Changes to show virtual ids to user

[Cedric Le Goater]

Hello !

>>> The worst case I can see with pid == 0.  Is that it would be a bug
>>> that we can fix later.  For other cases it would seem to be a user
>>> space API thing that we get stuck with for all time.
>> We cannot trust userspace application to expect some pid other than
>> positive. All that we can is either use some always-absent pid or
>> send the signal as SI_KERNEL.
>>
>> Our experience show that making decisions like above causes random
<>> applications failures that are hard (or even impossible) to debug.

> Ok.  So I guess I see what you are proposing is picking an arbitrary
> pid, say pid == 2, and reserving that in all pid namespaces and using
> it when we have a pid that does not map to a specific namespace. I'm
> fine with that.
> 
> All I care about is that we have a solution, preferably simple,
> to the non-mapped pid problem.

Pavel, are you against using pid == 0 and setting si_code to SI_KERNEL ? 

C.