[CRIU] problem using --cgroup-freezer?

[Tycho Andersen]

On Thu, Nov 19, 2015 at 04:07:42PM +0300, Pavel Emelyanov wrote:
> On 11/19/2015 12:06 PM, Andrew Vagin wrote:
> > On Wed, Nov 18, 2015 at 10:58:33AM -0700, Tycho Andersen wrote:
> >> On Wed, Nov 18, 2015 at 07:56:56AM -0700, Tycho Andersen wrote:
> >>> On Wed, Nov 18, 2015 at 10:25:20AM +0300, Andrew Vagin wrote:
> >>>> On Tue, Nov 17, 2015 at 03:15:30PM -0700, Tycho Andersen wrote:
> >>>>> Hi all,
> >>>>>
> >>>>> When I pass --cgroup-freezer to criu, the dump fails with the
> >>>>> following:
> >>>>>
> >>>>> (00.001376) Error (ptrace.c:140): Unseizable non-zombie 25021 found, state S, err -1/10
> >>>>> (00.001424) Error (ptrace.c:140): Unseizable non-zombie 25762 found, state S, err -1/10
> >>>>> (00.001469) Error (ptrace.c:140): Unseizable non-zombie 26046 found, state S, err -1/10
> >>>>> (00.001515) Error (ptrace.c:140): Unseizable non-zombie 26134 found, state S, err -1/10
> >>>>> (00.001560) Error (ptrace.c:140): Unseizable non-zombie 26151 found, state S, err -1/10
> >>>>> (00.001605) Error (ptrace.c:140): Unseizable non-zombie 26306 found, state S, err -1/10
> >>>>> (00.001650) Error (ptrace.c:140): Unseizable non-zombie 26357 found, state S, err -1/10
> >>>>> (00.001694) Error (ptrace.c:140): Unseizable non-zombie 26624 found, state S, err -1/10
> >>>>> (00.001740) Error (ptrace.c:140): Unseizable non-zombie 26636 found, state S, err -1/10
> >>>>> (00.001783) Error (ptrace.c:140): Unseizable non-zombie 26692 found, state S, err -1/10
> >>>>> (00.001833) Error (ptrace.c:140): Unseizable non-zombie 27075 found, state S, err -1/10
> >>>>> (00.001884) Error (ptrace.c:140): Unseizable non-zombie 27267 found, state S, err -1/10
> >>>>> (00.001930) Error (ptrace.c:140): Unseizable non-zombie 28380 found, state S, err -1/10
> >>>>> (00.001997) Error (ptrace.c:140): Unseizable non-zombie 25021 found, state S, err -1/10
> >>>>> (00.002039) Error (ptrace.c:140): Unseizable non-zombie 25762 found, state S, err -1/10
> >>>>> (00.002081) Error (ptrace.c:140): Unseizable non-zombie 26046 found, state S, err -1/10
> >>>>> (00.002123) Error (ptrace.c:140): Unseizable non-zombie 26134 found, state S, err -1/10
> >>>>> (00.002174) Error (ptrace.c:140): Unseizable non-zombie 26151 found, state S, err -1/10
> >>>>> (00.002218) Error (ptrace.c:140): Unseizable non-zombie 26306 found, state S, err -1/10
> >>>>> (00.002260) Error (ptrace.c:140): Unseizable non-zombie 26357 found, state S, err -1/10
> >>>>> (00.002305) Error (ptrace.c:140): Unseizable non-zombie 26624 found, state S, err -1/10
> >>>>> (00.002347) Error (ptrace.c:140): Unseizable non-zombie 26636 found, state S, err -1/10
> >>>>> (00.002390) Error (ptrace.c:140): Unseizable non-zombie 26692 found, state S, err -1/10
> >>>>> (00.002432) Error (ptrace.c:140): Unseizable non-zombie 27075 found, state S, err -1/10
> >>>>> (00.002474) Error (ptrace.c:140): Unseizable non-zombie 27267 found, state S, err -1/10
> >>>>> (00.002517) Error (ptrace.c:140): Unseizable non-zombie 28380 found, state S, err -1/10
> >>>>> (00.002563) Error (ptrace.c:43): Unable to detach from 23818: No such process
> >>>>
> >>>> Are all these processes in the freezer cgroup? Are they threads or
> >>>> thread leaders? Does the freezer group contain sub-groups?
> >>>
> >>> Ah, I think only the init process in the container is in the freezer
> >>> cgroup, the rest of them (the container's children) aren't somehow. I
> >>> suppose that's the source of the problem, but I don't understand how
> >>> that's possible...
> > 
> > So we need to add support of sub-groups. All this logic isn't freeze_processes().
> 
> Do you want to say that freezing a cgroup doesn't freeze sub-cgroups?

Sorry, I don't understand what you mean here.

I think he means that freeze_processes doesn't look at sup-cgroups in
order to find out which tasks to seize. IIUC freezing a cgroup should
freeze sub-cgroups.

I will look at sending a patch for this, thanks.

Tycho