[CRIU] lxc-checkpoint 1.1.5 works with criu 1.6.1 but not master

[Adrian Reber]

On Wed, Jan 13, 2016 at 04:18:31PM +0300, Pavel Emelyanov wrote:
> On 01/07/2016 01:04 PM, Adrian Reber wrote:
> > Hello Tycho,
> > 
> > thanks for your answers.
> > 
> > On Wed, Jan 06, 2016 at 07:15:25AM -0700, Tycho Andersen wrote:
> >> Hi Adrian,
> >>
> >> On Tue, Jan 05, 2016 at 06:47:55PM +0100, Adrian Reber wrote:
> >>> Running lxc-checkpoint works with CRIU 1.6.1 but not with today's
> >>> master.
> >>>
> >>> I get the following dump.log with today's master:
> >>>
> >>> (00.000250) Probing sock diag modules
> >>> (00.000280) Done probing
> >>> (00.000283) ========================================
> >>> (00.000286) Dumping processes (pid: 10794)
> >>> (00.000287) ========================================
> >>> (00.000289) Running pre-dump scripts
> >>> (00.000315) Found anon-shmem device at 4
> >>> (00.000321) Reset 16059's dirty tracking
> >>> (00.000329) Warn  (mem.c:56): Can't reset 16059's dirty memory tracker (22)
> >>> (00.000341) Unlock network
> >>> (00.000347) Unfreezing tasks into 1
> >>> (00.000352) Error (cr-dump.c:1578): Dumping FAILED.
> >>
> >> I've not seen this before. Based on a quick glance through the source,
> >> looks like the write() to /proc/pid/clear_refs is failing with EINVAL,
> >> which probably means your kernel is too old. Seems like this shouldn't
> >> be a fatal failure, though, as lxc-checkpoint doesn't try to use any
> >> memory tracking features.
> > 
> > I have always seen the dirty memory tracking warning, but as it is a
> > warning it has never been a problem before. It seems, however, that with
> > the following commit:
> > 
> > commit d10835c4ee0d0b1881b926708dee9877f5fb294d
> > Author: Pavel Emelyanov <xemul at parallels.com>
> > Date:   Tue Dec 15 22:25:09 2015 +0300
> > 
> >     dump: Dont read prohibited kernel files
> > 
> > criu now just aborts. Reverting this commits 'fixes' the broken master
> > behaviour.
> 
> :(
> 
> Would you check whether the patch titled 
> "[PATCH] kdat: Handle pagemaps with zeroed pfns"
> from the mailing list fixes it?

Unfortunately not. I had to change the last line of context of that
patch to get it applied, but a simple dump still fails:

# ./criu dump -D /tmp/3 -j -t `pidof minimal`  -v -v -v -v
(00.000035) Probing sock diag modules
(00.000072) Done probing
(00.000074) ========================================
(00.000076) Dumping processes (pid: 18737)
(00.000078) ========================================
(00.000081) Running pre-dump scripts
(00.000106) Pagemap is fully functional
(00.000136) Found anon-shmem device at 4
(00.000141) Reset 20624's dirty tracking
(00.000147) Warn  (mem.c:56): Can't reset 20624's dirty memory tracker (22)
(00.000160) Unlock network
(00.000167) Unfreezing tasks into 1
(00.000173) Error (cr-dump.c:1578): Dumping FAILED.

		Adrian