Re: [PATCH] pidns: limit the nesting depth of pid namespaces

[Andrew Morton]

On Wed, 24 Oct 2012 09:38:57 +0400
Andrey Wagin <avagin@xxxxxxxxx> wrote:

> >
> > I think that returning -ENOMEM in response to an excessive nesting
> > attempt is misleading - the system *didn't* run out of memory.  EINVAL
> > is better?
> 
> I chose ENOMEM by analogy with max_pid.  When a new PID can not be
> allocated, ENOMEM is returned too.

I don't know what this means - please be carefully specific when
identifying kernel code.

If you're referring to kernel/pid.c:alloc_pid() then -ENOMEM is
appropriate there, because a failure *is* caused by memory allocation
failure.

But ENOMEM isn't appropriate for nesting-depth-exceeded - we shouldn't
tell the user "you ran out of memory" when he didn't!  -EINVAL isn't
really appropriate either ("Invalid argument") but it has become a
general you-screwed-up catchall and seems to me to be the most
appropriate errno we have available.

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/