[CRIU] problem using --cgroup-freezer?

[Andrew Vagin]

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().

> 
> Oh, sorry, it's possible because some of the tasks are in sub-groups,
> which was the last part of your question.
> 
> Tycho