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

[richard -rw- weinberger]

On Tue, Jul 31, 2012 at 12:16 PM, Cyrill Gorcunov <gorcunov at openvz.org> wrote:
> 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 at parallels.com> 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.

If I do PR_SET_MM_START_BRK the if(!vma) will never be executed because
there a break in case PR_SET_MM_START_BRK.

-- 
Thanks,
//richard