Re: [Announce] Checkpoint-restore tool v0.1

From: Cyrill Gorcunov
Date: Tue Jul 31 2012 - 06:16:04 EST


On Tue, Jul 31, 2012 at 12:08:22PM +0200, richard -rw- weinberger wrote:
> On Tue, Jul 31, 2012 at 11:54 AM, Pavel Emelyanov <xemul@xxxxxxxxxxxxx> wrote:
> >> Yeah, but I fear it's not that easy.
> >> We'd have to change crtools to work without ptrace().
> >
> > Well, this is hard. Using ptrace saved us from having many special-purpose
> > APIs for dumping various stuff (there will be an article about it). Thus I
> > don't know which way is simpler -- stop using ptrace or teach ptrece to allow
> > several tracers to attach to one task %)
>
> Allowing multiple tracers in a safe way is IMHO even more harder.
>
> BTW: While reading prctl_set_mm() I noticed two things.
> 1. Why isn't the return value of find_vma() verified?

prctl_set_mm
vma = find_vma(mm, addr);
...
if (!vma) {
error = -EFAULT;
goto out;
}

these values are used in procfs statistics only. So I don't get
which verify you mean here.

> It looks like one can set an addr which does not belong to any vma.
> 2. What will happen if addr is not page aligned?

you'll have a bit weird output in procfs stat (probably I should add
page alignment check here).

Cyrill
--
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/